feat: Detect repetition of common words

[elijah-potter]

Harper should include a linting rule that detects and repairs incorrect repetition of common words.

Examples that should throw a lint:

She lifted the the rock.

I will will do it later.

Examples that should not throw a lint:

This is very very difficult.

While the above example could be grammatically improved by removing the repetition, it is not a grammatical error. This improvement should be a separate lint.

[elijah-potter]

This has been implemented in the repeated_words linter. If a common enough word should be analyzed for repetition, reopen this issue.