Detect duplicates of "the the"

[cmichi]

Is your feature request related to a particular use-case?

I just discovered that the ink! codebase has quite a number of "the the" occurrences: https://github.com/paritytech/ink/pull/856/commits/4ac7691e65ab2b1ce7034c432914f651573739dc.

Describe the solution you'd like to implement/see implemented

AFAIK there is no legitimate use of "the the", hence cargo-spellcheck could flag those.

[drahnr]

The difficult with those special rules is: there are plenty of those special patterns could be added, but I think it'd require a systematic approach allow multi tokens to be represented. And that would quickly require the token structure provided by nlprule, so I think providing custom rules and documenting that properly is the only way to make this feasable without introducing tons of special cases.

The basic functionality of adding a custom nlpruleset is already there, it's mostly a matter of documenting how to write / expand it with custom ones and make that something easy to do.