feat: Adding `codespell` to Automatically Check Spelling

[yhakbar]

Description

We've had a couple typos cause problems in the past. This introduces some automated spellchecking to make sure we're not making obvious spelling mistakes.

It seems very unlikely to cause false positives, at the risk of potentially allowing some false negatives. We still need to be mindful when reviewing that we check spelling, etc.

TODOs

Read the Gruntwork contribution guidelines.

• [x] Update the docs.
• [x] Run the relevant tests successfully, including pre-commit checks.
• [x] Ensure any 3rd party code adheres with our license policy or delete this line if its not applicable.
• [x] Include release notes. If this PR is backward incompatible, include a migration guide.

Release Notes (draft)

Added codespell to CI.