Resolve review comments

Author: yuzhichang

rag/utils/infinity_conn.py

@@ -719,7 +719,7 @@ def getHighlight(self, res: tuple[pd.DataFrame, int] | pd.DataFrame, keywords: l
                 else:
                     for w in sorted(keywords, key=len, reverse=True):
                         t = re.sub(
-                            w,
+                            re.escape(w),
                             f"<em>{w}</em>",
                             t,
                             flags=re.IGNORECASE | re.MULTILINE,