Fix doc spelling errors after updates in vale rules (Infra)

[tang-mm]

Description

This PR fixes false-negative spelling errors in documentation.

Due to the previous scoping issue with the spelling check tool, spelling errors in the documentation were not reported in previous checks. With the fix in Vale release v1.30.0, scoping was updated in the upstream canonical/documentation-style-guide repository, so more spelling errors are reported in new PRs.

Attaching the announcement for reference:

Doc check update: Vale based spelling
Due to issues with some Vale scopes, the updated spelling check was unable to capture all relevant cases. This issue has been resolved, which will likely flag additional spelling issues in your documentation repositories.
For false positives: If the false positive is a product specific term, please add it to your .custom_wordlist.txt file. If the false positive is a dictionary term, or a term that should be ignored Canonical-wide, please create an issue in our style guide repository indicating the term.

Resolved issues

NA

Documentation

NA

Tests

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