Handle Single Quotes Properly

[ColonelPanics]

Overview

The current word separation in mkdocs-spellcheck causes words like isn't, wouldn't etc to be split such that they are checked as isn and wouldn, leading to erroneous warnings about misspelling.

This PR modifies the regex for separating out words. Previously this regex would only check letters and spaces, now it also removes:

• "Non-word boundaries" (\B) preceding, following or surrounding a word (this means that single quotes can be used to surround a word without being retained for spellchecking)
• Possessive noun endings ('s), this means that the word preceding the 's will be checked against the dictionary

Steps to Test

Tested with:

• Mkdocs v1.5.2
• mkdocs-spellcheck v1.0.0

Steps:

• Create a new mkdocs installation with mkdocs new mydocs
• Setup mkdocs.yml in the new directory to look as follows:

  site_name: My Docs
  plugins:
  - spellcheck:
      backends:
        - symspellpy
        - codespell

• Set docs/index.md to contain the following

  This isn't normally matched, I've 'quoted' something that shouldn't be used for spellcheck.
  
  This Pull Request increases the plugin's power!
  
  isn

• In my local instance, I hacked the regex changes into the plugin file to quickly test it

• Run mkdocs serve -s and only an error for isn should be returned (Note: I've left in these deprecation warnings as these may be something else that needs fixing)

  $ mkdocs serve -s
  INFO    -  DeprecationWarning: warning_filter doesn't do anything since MkDocs 1.2 and will be removed soon. All messages on the `mkdocs` logger
             get counted automatically.
               File "/opt/homebrew/lib/python3.11/site-packages/mkdocs_spellcheck/loggers.py", line 8, in <module>
                 from mkdocs.utils import warning_filter
               File "/opt/homebrew/lib/python3.11/site-packages/mkdocs/utils/__init__.py", line 453, in __getattr__
                 warnings.warn(
  INFO    -  Building documentation...
  INFO    -  DeprecationWarning: path is deprecated. Use files() instead. Refer to
             https://importlib-resources.readthedocs.io/en/latest/using.html#migrating-from-legacy for migration advice.
               File "/opt/homebrew/lib/python3.11/site-packages/mkdocs_spellcheck/backends/symspellpy.py", line 31, in __init__
                 with resources.path("symspellpy", "frequency_dictionary_en_82_765.txt") as dictionary_path:
           File
             "/opt/homebrew/Cellar/python@3.11/3.11.4_1/Frameworks/Python.framework/Versions/3.11/lib/python3.11/importlib/resources/_legacy.py",
             line 18, in wrapper
                 warnings.warn(
  INFO    -  Cleaning site directory
  WARNING -  mkdocs_spellcheck: (symspellpy) index.md: Misspelled 'isn', did you mean 'in', 'is', 'inn', 'sin', 'ian', 'ion', 'ign', 'isl', 'ism'?
  
  Aborted with 1 warnings in strict mode!

[pawamoy]

Hello, thanks a lot, that's great!

I like how you split the change into three commits, however to rebase as is, I would like that you prefix the first and last one with the fix: type, and the second one with the refactor: type.

Otherwise if you're OK with squashing I can do that too.

[pawamoy]

Also don't worry about the CI failure, I'll take care of it, it's unrelated to your changes.

[ColonelPanics]

Thanks for the feedback @pawamoy! I've tweaked and force-pushed the message changes. Let me know if there's anything else you need from me.

Thanks for your useful plugin

[pawamoy]

Perfect, thanks!

[pawamoy]

I fixed the deprecation warning and released your change as part of v1.0.1 :slightly_smiling_face: