Feature Request: Smart In-word completion

[adaszko]

It'd be nice if completion candidates were filtered not only based on the prefix but also consider the suffix if completing in the middle of a word (e.g. foo_<TAB>_baz). If there's a space after the cursor, this feature doesn't apply.

Behavior specification:

Let's assume I'm completing foo_|_baz with the cursor positition indicated by |.

Case 1. I have foo_bar_baz somewhere in completion sources. The completion should result in foo_bar_baz.
Case 2. I don't have anything matching the wildcard foo_*_baz in the completion sources but have foo_quux. The completion should then fallback to matching just the prefix and result in completing to foo_quux_baz.

[Saghen]

This one has been moved from config.fuzzy.keyword_range to config.trigger.completion.keyword_range