Improve the error case for textwrap.dedent

Author: AA-Turner

Lib/textwrap.py

@@ -429,7 +429,11 @@ def dedent(text):
     if not text:
         return text
 
-    lines = text.split('\n')
+    try:
+        lines = text.split('\n')
+    except AttributeError:
+        msg = f'expected str object, not {type(text).__qualname__!r}'
+        raise TypeError(msg) from None
 
     # Get length of leading whitespace, inspired by ``os.path.commonprefix()``.
     non_blank_lines = [l for l in lines if l and not l.isspace()]

Misc/NEWS.d/3.14.0a7.rst

@@ -288,7 +288,7 @@ Improve the import time of the :mod:`ast` module by extracting the
 .. nonce: 8M-HVz
 .. section: Library
 
-Improved performance of :func:`textwrap.dedent` by an average of ~1.3x.
+Improved performance of :func:`textwrap.indent` by an average of ~1.3x.
 Patch by Adam Turner.
 
 ..