codespell: Move options into .codespellrc

Previously, options were listed in the github workflow file, but by
moving them into the .codespellrc file you can also just run the
`codespell` command locally to see the same results as in the github
workflow.

This also fixes the options (using ignore-words-list as an actual list
instead of pointing to a file like ignore-words is intended for) and
uses skip to exclude files instead of exclude-file which seems intended
to point to a file containing excludes.

Additionally, this tweaks the options a bit (adding more skips) and
removes the codespell-ignore-words-list.txt file (putting them in the
.codespellrc file directly).

Author: matthijskooijman

.codespellrc

@@ -0,0 +1,7 @@
+[codespell]
+skip = ./src/STM32CubeWL,./src/BSP/timer_if.*,./api-docs,./.git
+# The presence of these values enables them
+check-filenames =
+check-hidden =
+# In the event of a false positive, add the word in all lower case to this value (comma-separated string)
+ignore-words-list = wan

.github/workflows/CodeSpell.yml

@@ -19,9 +19,3 @@ jobs:
       # See: https://github.com/codespell-project/actions-codespell/blob/master/README.md
       - name: Spell check
         uses: codespell-project/actions-codespell@master
-        with:
-          check_filenames: true
-          check_hidden: true
-          # In the event of a false positive, add the word in all lower case to this file:
-          ignore-words-list: "./extras/codespell-ignore-words-list.txt"
-          exclude_file: src/STM32CubeWL