[NFC] Update comments in code

Signed-off-by: yronglin <[email protected]>

Author: yronglin

clang/include/clang/Lex/Preprocessor.h

@@ -350,7 +350,7 @@ class Preprocessor {
   /// Whether the last token we lexed was an '@'.
   bool LastTokenWasAt = false;
 
-  /// First pp-token in current translation unit.
+  /// First pp-token source location in current translation unit.
   SourceLocation FirstPPTokenLoc;
 
   /// A position within a C++20 import-seq.

clang/include/clang/Lex/TokenLexer.h

@@ -139,8 +139,9 @@ class TokenLexer {
   void Init(const Token *TokArray, unsigned NumToks, bool DisableMacroExpansion,
             bool OwnsTokens, bool IsReinject);
 
-  /// If the next token lexed will pop this macro off the expansion stack,
-  /// return std::nullopt, otherwise return the next unexpanded token.
+  /// If TokenLexer::isAtEnd returns true (the next token lexed will pop this
+  /// macro off the expansion stack, return std::nullopt, otherwise return the
+  /// next unexpanded token.
   std::optional<Token> peekNextPPToken() const;
 
   /// Lex and return a token from this macro stream.