11662: fix: extract_module selection inside impl r=Veykril a=feniljain
Should close: #11508
From issue:
Concern 1: Seems to be fixed in latest `rust-analyzer` build
Concern 2 and 3: Should be fixed by this PR
Concern 4: Got fixed in #11472
Points to note:
- Here I have seperated use items and other items, this is becuase the new `impl` block which we will be creating cannot contain use items as immediate children. As they are the only one item that can be generated by our assist, so seperating them helps in handling their inclusion in new `impl` block inside new `module`
- There's also a new method added which helps in removing remaning left over indentation after removing `impl` or other `item`
Co-authored-by: vi_mi <fkjainco@gmail.com>
a7d440e368