Get rid of import_sorter

As much as I love import_sorter, it's an extra overhead that I need to
remember, as do external contributors, and that's not feasible.

Or well it is, but the gain is very little.

Author: vHanda

Makefile

@@ -1,6 +1,3 @@
-fmt:
-	dart run import_sorter:main
-
 lint:
 	dart analyze
 

pubspec.yaml

@@ -25,13 +25,10 @@ dependencies:
 dev_dependencies:
   archive: ^3.3.5
   build_runner:
-  import_sorter: ^4.6.0
   lints: ^3.0.0
   process_run: ^0.12.5+2
   test:
 
 environment:
   sdk: ">=3.0.0 <4.0.0"
 
-import_sorter:
-  comments: false