Remove duplicate suggestions

[tDeContes]

Background

It would be nice that the context menu doesn't suggest useless items. (I'm using only casing.)
For ex when I ask for i, it suggests i/I/I/I.

Proposed solution

For each suggested text transformation, after the transformation is made, check whether:

• it's the same as original,
• it's already suggested upper.

If yes, remove the item.

It would also be useful for code casing, in all cases where is there only one word to handle.
I don't think it would be useful for those with special characters.

Alternatives

It could be seen as an alternative to #30, although it is more of a complement.