Fix up STJ comments

xml/System.Text.Json.Serialization.Metadata/JsonObjectInfoValues`1.xml

@@ -26,15 +26,7 @@
   <Docs>
     <typeparam name="T">The object type to serialize or deserialize.</typeparam>
     <summary>Provides serialization metadata about an object type with constructors, properties, and fields.</summary>
-    <remarks>
-      <format type="text/markdown"><![CDATA[
-
-## Remarks
-
-This API is intended for use by the output of the System.Text.Json source generator and should not be called directly.
-
-      ]]></format>
-    </remarks>
+    <remarks>This API is intended for use by the output of the System.Text.Json source generator and should not be called directly.</remarks>
   </Docs>
   <Members>
     <Member MemberName=".ctor">

xml/System.Text.Json.Serialization.Metadata/JsonParameterInfoValues.xml

@@ -22,15 +22,7 @@
   </Attributes>
   <Docs>
     <summary>Provides information about a constructor parameter required for JSON deserialization.</summary>
-    <remarks>
-      <format type="text/markdown"><![CDATA[
-
-## Remarks
-
-This API is intended for use by the output of the System.Text.Json source generator and should not be called directly.
-
-      ]]></format>
-    </remarks>
+    <remarks>This API is intended for use by the output of the System.Text.Json source generator and should not be called directly.</remarks>
   </Docs>
   <Members>
     <Member MemberName=".ctor">

xml/System.Text.Json.Serialization.Metadata/JsonPropertyInfo.xml

@@ -16,15 +16,7 @@
   <Interfaces />
   <Docs>
     <summary>Provides JSON serialization-related metadata about a property or field.</summary>
-    <remarks>
-      <format type="text/markdown"><![CDATA[
-
-## Remarks
-
-This API is intended for use by the output of the System.Text.Json source generator and should not be called directly.
-
-      ]]></format>
-    </remarks>
+    <remarks>To be added.</remarks>
   </Docs>
   <Members>
     <Member MemberName="AttributeProvider">
@@ -177,10 +169,21 @@ The current <see cref="P:System.Text.Json.Serialization.Metadata.JsonPropertyInf
       <Docs>
         <summary>Gets or sets a value that indicates whether the current property is required for deserialization to be successful.</summary>
         <value>To be added.</value>
-        <remarks>For contracts originating from <see cref="T:System.Text.Json.Serialization.Metadata.DefaultJsonTypeInfoResolver" /> or <see cref="T:System.Text.Json.Serialization.JsonSerializerContext" />, the value of this property will be mapped from <see cref="T:System.Text.Json.Serialization.JsonRequiredAttribute" /> annotations.
-             For contracts using <see cref="T:System.Text.Json.Serialization.Metadata.DefaultJsonTypeInfoResolver" />, the value of this property will also map from properties that have the <see langword="required" /> modifier, unless deserialization uses a constructor that populates all required properties and that has <see cref="T:System.Diagnostics.CodeAnalysis.SetsRequiredMembersAttribute" />.
-             <see langword="required" /> keyword is currently not supported in <see cref="T:System.Text.Json.Serialization.JsonSerializerContext" /> contracts.</remarks>
+        <remarks>
+          <format type="text/markdown"><![CDATA[
+
+## Remarks
+
+For contracts that originate from <xref:System.Text.Json.Serialization.Metadata.DefaultJsonTypeInfoResolver> or <xref:System.Text.Json.Serialization.JsonSerializerContext>, the value of this property is mapped from <xref:System.Text.Json.Serialization.JsonRequiredAttribute> annotations.
+
+For contracts that use <xref:System.Text.Json.Serialization.Metadata.DefaultJsonTypeInfoResolver>, the value of this property is also mapped from properties that have the `required` modifier, unless deserialization uses a constructor that populates all required properties and has <xref:System.Diagnostics.CodeAnalysis.SetsRequiredMembersAttribute>.
+
+The `required` keyword is currently not supported in <xref:System.Text.Json.Serialization.JsonSerializerContext> contracts.
+
+]]></format>
+        </remarks>
         <exception cref="T:System.InvalidOperationException">The <see cref="T:System.Text.Json.Serialization.Metadata.JsonPropertyInfo" /> instance has been locked for further modification.</exception>
+        <related type="Article" href="/dotnet/standard/serialization/system-text-json/required-properties">Required properties</related>
       </Docs>
     </Member>
     <Member MemberName="Name">

xml/System.Text.Json.Serialization.Metadata/JsonTypeInfo.xml

@@ -20,15 +20,7 @@
   <Interfaces />
   <Docs>
     <summary>Provides JSON serialization-related metadata about a type.</summary>
-    <remarks>
-      <format type="text/markdown"><![CDATA[
-
-## Remarks
-
-This API is intended for use by the output of the System.Text.Json source generator and should not be called directly.
-
-      ]]></format>
-    </remarks>
+    <remarks>To be added.</remarks>
   </Docs>
   <Members>
     <Member MemberName="Converter">