doc: fixed typo in file name format (#14191)

Author: lwu1822

doc/en/how-to/usage.rst

@@ -7,7 +7,7 @@ How to invoke pytest
 ..  seealso:: :ref:`Complete pytest command-line flags reference <command-line-flags>`
 
 In general, pytest is invoked with the command ``pytest`` (see below for :ref:`other ways to invoke pytest
-<invoke-other>`). This will execute all tests in all files whose names follow the form ``test_*.py`` or ``\*_test.py``
+<invoke-other>`). This will execute all tests in all files whose names follow the form ``test_*.py`` or ``*_test.py``
 in the current directory and its subdirectories. More generally, pytest follows :ref:`standard test discovery rules
 <test discovery>`.