revert UserInsert message

Author: willmcgugan

src/textual/content.py

@@ -1499,6 +1499,8 @@ def highlight_regex(
         plain = self.plain
         if isinstance(highlight_regex, str):
             re_highlight = re.compile(highlight_regex)
+        else:
+            re_highlight = highlight_regex
         count = 0
         for match in re_highlight.finditer(plain):
             start, end = match.span()

src/textual/widgets/_text_area.py

@@ -446,23 +446,6 @@ class SelectionChanged(Message):
         def control(self) -> TextArea:
             return self.text_area
 
-    @dataclass
-    class UserInsert(Message):
-        """Posted when the user has entered text via the keyboard."""
-
-        location: Location
-        """The location where the text was added."""
-
-        text: str
-        """The text that was entered."""
-
-        text_area: TextArea
-        """The `text_area` that sent this message."""
-
-        @property
-        def control(self) -> TextArea:
-            return self.text_area
-
     def __init__(
         self,
         text: str = "",
@@ -2443,7 +2426,6 @@ def _replace_via_keyboard(
         """
         if self.read_only:
             return None
-        self.post_message(self.UserInsert(start, insert, self))
         return self.replace(insert, start, end, maintain_selection_offset=False)
 
     def action_delete_left(self) -> None: