docs(auto-reply): align silent token comment with regex

src/auto-reply/tokens.ts

@@ -11,8 +11,8 @@ export function isSilentReplyText(
     return false;
   }
   const escaped = escapeRegExp(token);
-  // Only match when the entire response (trimmed) is the silent token,
-  // optionally surrounded by whitespace. This prevents
+  // Match only the exact silent token with optional surrounding whitespace.
+  // This prevents
   // substantive replies ending with NO_REPLY from being suppressed (#19537).
   return new RegExp(`^\\s*${escaped}\\s*$`).test(text);
 }