Apply suggestions from code review

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: cbornet

libs/core/langchain_core/messages/tool.py

@@ -333,7 +333,6 @@ def default_tool_parser(
 
     Returns:
         A list of tool calls and invalid tool calls.
-    .
     """
     tool_calls = []
     invalid_tool_calls = []

libs/core/langchain_core/utils/mustache.py

@@ -331,7 +331,7 @@ def tokenize(
 
 
 def _html_escape(string: str) -> str:
-    """Return the HTML escaped of all of these " & < >."""
+    """Return the HTML-escaped string with all of these characters escaped: " & < >."""
     html_codes = {
         '"': "&quot;",
         "<": "&lt;",