[RULE]: Add words to avoid rule to linter

[JC-DSIT]

Proposed changes

• add words-to-avoid.yml
• update README.md
• add words-to-avoid-unless.yml rule
• add BDD tests

Adds two new linting rules:

• words-to-avoid which raises an error for any of the straightforward words to avoid (e.g. initiate, use ‘start’ or ‘begin’)
• words-to-avoid-unless which raises a warning if there is a time it may be used (e.g. slim down (unless talking about one’s waistline), use ‘make smaller’ or ‘reduce the size’)

What changed

Adds new rules, extends the linter coverage and the ability to consistently highlight and review content.

Related issue or tracking reference

You should have an open GitHub issue that this PR will fix.

• Fixes [Rule]: Highlight use of words to avoid #28
• Relates to There is not a finalised, definitive list of prioritised style guide rules #7

Related feature files

To help us understand the change, please either list or link to any feature files or scenarios that explain the new behaviour

TBC

Checklist

Before you request approval you should confirm that:

• the pull request has a clear title with a short description about the update in the documentation
• you have added, updated or removed any scenarios affected by the change
• GitHub actions all pass
• you have linked this PR to an issue (or explained why none exists)
• you have updated documentation if needed