Fix false positives in automated spellchecking

By adding an --exclude-file argument, we can add exact lines that
will be matched against to ignore. This prevents us having to add
a word such as "juxt" to the ignored words list when we usually want
to catch that as a misspelling of "just" except in one context.

With all spelling errors fixed and false-positives ignored, the status
of codespell run on each commit can now be trusted.

If any of the lines specified in cs-excludelines.txt need to be modified
in the README, they just need to be adjusted both places.

.github/workflows/spell_checking.yml

@@ -21,7 +21,7 @@ jobs:
           pip install codespell
           if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
       - name: Check spelling with codespell
-        run: codespell --ignore-words=codespell.txt || exit 1
+        run: codespell --ignore-words=cs-ignorewords.txt --exclude-file=cs-excludelines.txt || exit 1
   misspell:
     name: Check spelling with misspell
     runs-on: ubuntu-latest

cs-excludelines.txt

@@ -0,0 +1,3 @@
+:source-highlighter: rouge
+gem install rouge
+((juxt :a :b) {:a "ala" :b "bala"})