docs: update function name from get_version() to get_versions() (#4945)

Author: Devesh-Yadav10

test/README.md

@@ -159,7 +159,7 @@ To test the filename mappings, rather than making a bunch of empty files, we're
     )
 ```
 
-The function `test_filename_is` will then load the checker you have specified (and fail spectacularly if you specify a checker that does not exist), try to run `get_version()` with an empty file content and the filename you specified, then check that it "is" something (as opposed to "contains") and that the modulename that `get_version` returns is in fact the `expected_result` you specified.
+The function `test_filename_is` will then load the checker you have specified (and fail spectacularly if you specify a checker that does not exist), try to run `get_versions()` with an empty file content and the filename you specified, then check that it "is" something (as opposed to "contains") and that the modulename that `get_versions` returns is in fact the `expected_result` you specified.
 
 For ease of maintenance, please keep the parametrize list in alphabetical order when you add a new tests.