Adding needed Tokenizer's APIs (#7047)

* Adding needed Tokenizer's APIs

* Address the feedback

* Small update to the newly exposed APIs

* fix comments

* Update the APIs signatures

* More feedback addressing

* Fix the comments

src/Microsoft.ML.Tokenizers/Model/BPE.cs

@@ -176,8 +176,8 @@ private Bpe(Stream vocabStream, Stream? mergesStream, string? unknownToken, stri
         /// <summary>
         /// Encode a text string to a list of tokens.
         /// </summary>
-        /// <param name="text">The text to encode.</param>
-        /// <param name="isSpecialToken">Indicate if the token is a special token.</param>
+        /// <param name="text">The text to encode. If the value of the parameter <paramref name="isSpecialToken"/> is true, the entire text will be treated as a special token.</param>
+        /// <param name="isSpecialToken">Specifies whether the entire <paramref name="text"/> is considered a special token. This parameter is ignored in this model.</param>
         /// <returns>The list of tokens generated from the text tokenization.</returns>
         public override IReadOnlyList<Token> Encode(string text, bool isSpecialToken = false)
         {
@@ -192,17 +192,17 @@ public override IReadOnlyList<Token> Encode(string text, bool isSpecialToken = f
         /// <summary>
         /// Encode a split text string to a list of Ids and add them to the accumulatedIds list.
         /// </summary>
-        /// <param name="text">The text to split.</param>
-        /// <param name="isSpecialToken">Indicate if the token is a special token.</param>
+        /// <param name="text">The text to encode. If the value of the parameter <paramref name="isSpecialToken"/> is true, the entire text will be treated as a special token.</param>
+        /// <param name="isSpecialToken">Specifies whether the entire <paramref name="text"/> is considered a special token. This parameter is ignored in this model.</param>
         /// <param name="accumulatedIds">The list of accumulated encoded Ids.</param>
         public override void EncodeToIds(ReadOnlySpan<char> text, bool isSpecialToken, IList<int> accumulatedIds) => EncodeToIdsWithCache(text, accumulatedIds);
 
         /// <summary>
         /// Get the number of tokens that the input text will be encoded to.
         /// </summary>
-        /// <param name="text">The text to encode.</param>
-        /// <param name="isSpecialToken">Indicate if the token is special token.</param>
-        /// <returns>The number of tokens that the input text will be encoded to.</returns>
+        /// <param name="text">The text to encode. If the value of the parameter <paramref name="isSpecialToken"/> is true, the entire text will be treated as a special token.</param>
+        /// <param name="isSpecialToken">Specifies whether the entire <paramref name="text"/> is considered a special token. This parameter is ignored in this model.</param>
+        /// <returns>The number of tokens that the input text will be encoded to. This parameter is ignored in this model.</returns>
         public override int CountTokens(ReadOnlySpan<char> text, bool isSpecialToken) => EncodeToIdsWithCache(text, null);
 
         /// <summary>

src/Microsoft.ML.Tokenizers/Model/EnglishRoberta.cs

@@ -176,8 +176,8 @@ public EnglishRoberta(Stream vocabularyStream, Stream mergeStream, Stream highes
         /// <summary>
         /// Encode a text string to a list of tokens.
         /// </summary>
-        /// <param name="text">The text to encode.</param>
-        /// <param name="isSpecialToken">Indicate if the token is a special token.</param>
+        /// <param name="text">The text to encode. If the value of the parameter <paramref name="isSpecialToken"/> is true, the entire text will be treated as a special token.</param>
+        /// <param name="isSpecialToken">Specifies whether the entire <paramref name="text"/> is considered a special token. This parameter is ignored in this model.</param>
         /// <returns>The list of tokens generated from the text tokenization.</returns>
         public override IReadOnlyList<Token> Encode(string text, bool isSpecialToken = false)
         {
@@ -224,16 +224,16 @@ public override IReadOnlyList<Token> Encode(string text, bool isSpecialToken = f
         /// <summary>
         /// Encode a split text string to a list of Ids and add them to the accumulatedIds list.
         /// </summary>
-        /// <param name="text">The text to split.</param>
-        /// <param name="isSpecialToken">Indicate if the token is a special token.</param>
+        /// <param name="text">The text to encode. If the value of the parameter <paramref name="isSpecialToken"/> is true, the entire text will be treated as a special token.</param>
+        /// <param name="isSpecialToken">Specifies whether the entire <paramref name="text"/> is considered a special token. This parameter is ignored in this model.</param>
         /// <param name="accumulatedIds">The list of accumulated encoded Ids.</param>
         public override void EncodeToIds(ReadOnlySpan<char> text, bool isSpecialToken, IList<int> accumulatedIds) => EncodeToIds(text, accumulatedIds);
 
         /// <summary>
         /// Get the number of tokens that the input text will be encoded to.
         /// </summary>
-        /// <param name="text">The text to encode.</param>
-        /// <param name="isSpecialToken">Indicate if the token is special token.</param>
+        /// <param name="text">The text to encode. If the value of the parameter <paramref name="isSpecialToken"/> is true, the entire text will be treated as a special token.</param>
+        /// <param name="isSpecialToken">Specifies whether the entire <paramref name="text"/> is considered a special token. This parameter is ignored in this model.</param>
         /// <returns>The number of tokens that the input text will be encoded to.</returns>
         public override int CountTokens(ReadOnlySpan<char> text, bool isSpecialToken) => EncodeToIds(text, null);
 

src/Microsoft.ML.Tokenizers/Model/Model.cs

@@ -16,16 +16,16 @@ public abstract class Model
         /// <summary>
         /// Encode a text to a list of tokens.
         /// </summary>
-        /// <param name="text">The text to encode.</param>
-        /// <param name="isSpecialToken">Indicate if the token is a special token.</param>
+        /// <param name="text">The text to encode. If the value of the parameter <paramref name="isSpecialToken"/> is true, the entire text will be treated as a special token.</param>
+        /// <param name="isSpecialToken">Specifies whether the entire <paramref name="text"/> is considered a special token.</param>
         /// <returns>The list of tokens generated from the text tokenization.</returns>
         public abstract IReadOnlyList<Token> Encode(string text, bool isSpecialToken = false);
 
         /// <summary>
         /// Encode a text to a list of Ids and add them to the accumulatedIds list.
         /// </summary>
-        /// <param name="text">The text to encode.</param>
-        /// <param name="isSpecialToken">Indicate if the token is a special token.</param>
+        /// <param name="text">The text to encode. If the value of the parameter <paramref name="isSpecialToken"/> is true, the entire text will be treated as a special token.</param>
+        /// <param name="isSpecialToken">Specifies whether the entire <paramref name="text"/> is considered a special token.</param>
         /// <param name="accumulatedIds">The list of accumulated encoded Ids.</param>
         /// <remarks>
         /// This method does the default implementation that uses the Encode method to get the token's Ids.
@@ -49,8 +49,8 @@ public virtual void EncodeToIds(ReadOnlySpan<char> text, bool isSpecialToken, IL
         /// <summary>
         /// Get the number of tokens that the input text will be encoded to.
         /// </summary>
-        /// <param name="text">The text to encode.</param>
-        /// <param name="isSpecialToken">Indicate if the token is special token.</param>
+        /// <param name="text">The text to encode. If the value of the parameter <paramref name="isSpecialToken"/> is true, the entire text will be treated as a special token.</param>
+        /// <param name="isSpecialToken">Specifies whether the entire <paramref name="text"/> is considered a special token.</param>
         /// <returns>The number of tokens that the input text will be encoded to.</returns>
         /// <remarks>
         /// This method does the default implementation that uses the EncodeToIds method to get the number of token's Ids.