Fix warnings in docs build #171

Running mkdocs locally I noticed there are some warnings about undocumented args etc. (see below). I don't think we should fix that now, but do you think it's worth opening an issue about? You can fail the CI on warnings if you add the --strict flag to mkdocs build and we're done that in some other projects.

❮ mkdocs build
INFO    -  Cleaning site directory
INFO    -  Building documentation to directory: /home/alex/code/Auto-CORPus/site
WARNING -  griffe: autocorpus/table.py:171: No type or annotation for parameter 's'
WARNING -  griffe: autocorpus/table.py:174: No type or annotation for returned value 1
WARNING -  griffe: autocorpus/utils.py:111: No type or annotation for returned value 1
WARNING -  griffe: autocorpus/utils.py:18: No type or annotation for parameter
           'base_dir'
WARNING -  griffe: autocorpus/utils.py:19: No type or annotation for parameter
           'pattern'
WARNING -  griffe: autocorpus/utils.py:199: No type or annotation for returned value 2
WARNING -  griffe: autocorpus/utils.py:200: No type or annotation for returned value 3
WARNING -  griffe: autocorpus/utils.py:201: No type or annotation for returned value 4
WARNING -  griffe: autocorpus/utils.py:202: No type or annotation for returned value 5
WARNING -  griffe: autocorpus/utils.py:314: No type or annotation for returned value 1
INFO    -  Documentation built in 0.94 seconds

Originally posted by @alexdewar in #170 (review)