Fix a typo in CODEOWNERS (#157356)

Author: StanFromIreland

.github/CODEOWNERS

@@ -630,7 +630,7 @@ Lib/test/test_unittest/testmock/ @cjw296
 Doc/library/zlib.rst          @StanFromIreland
 Lib/compression/zlib.py       @StanFromIreland
 Lib/test/test_zlib.py         @StanFromIreland
-Modules/_zlibmodule.c         @StanFromIreland
+Modules/zlibmodule.c          @StanFromIreland
 
 # Zipfile.Path
 Lib/test/test_zipfile/_path/  @jaraco