Remove completion limit for trait importing method completions
Fixes https://github.com/rust-lang/rust-analyzer/issues/16075
The < 3 char limit never applied to methods and the amount of completions generated due this is not absolutely massive as not all traits in a project are ever applicable so there is little reason to employ the limit here. Especially as it limits the number of traits we consider, not items (after my changes yesterday), and the number of traits is not the slowing factor here. Tested this in r-a where we have ~800 traits project wide and even when ~260 are applicable there was no noticable slow down from it.
dc31cef5fc