fixup! clarifying comments

GitUI/Editor/Diff/DiffHighlightService.cs

@@ -124,6 +124,7 @@ public override void AddTextHighlighting(IDocument document)
 
     /// <summary>
     /// Parse the text in the document from line and return the added lines directly following.
+    /// Overridden in the HighlightServices where GE coloring is used (AddTextHighlighting() for Patch and CombinedDiff).
     /// </summary>
     /// <param name="document">The document to analyze.</param>
     /// <param name="line">The line number to start with, updated with the last line processed.</param>
@@ -134,6 +135,7 @@ protected virtual List<ISegment> GetAddedLines(IDocument document, ref int line,
 
     /// <summary>
     /// Parse the text in the document from line and return the removed lines directly following.
+    /// Overridden in the HighlightServices where GE coloring is used (AddTextHighlighting() for Patch and CombinedDiff).
     /// </summary>
     /// <param name="document">The document to analyze.</param>
     /// <param name="line">The line number to start with, updated with the last line processed.</param>
@@ -144,14 +146,14 @@ protected virtual List<ISegment> GetRemovedLines(IDocument document, ref int lin
 
     /// <summary>
     /// Highlight the directly following lines.
-    ///
+    /// Overridden in the HighlightServices where GE coloring is used (AddTextHighlighting() for Patch and CombinedDiff).
     /// </summary>
     /// <param name="document">The document to analyze.</param>
     /// <param name="line">The line number to start with.</param>
     /// <param name="lineSegment">The segment for the starting line.</param>
     /// <returns>The last line number processed.</returns>
     protected virtual int TryHighlightAddedAndDeletedLines(IDocument document, int line, LineSegment lineSegment)
-        => 0;
+        => line;
 
     protected void ProcessLineSegment(IDocument document, ref int line,
         LineSegment lineSegment, string prefixStr, Color color, bool invertMatch = false)