Add cargo,completion.bash to clean_files.txt & run lint.

clean_files.txt

@@ -31,3 +31,4 @@ themes/powerline
 # completions
 #
 completion/available/rustup.completion.bash
+completion/available/cargo.completion.bash

completion/available/cargo.completion.bash

@@ -11,7 +11,7 @@ fi
 # Default bash version is 3.2 on latest macOS. See #6874
 shopt -s extglob
 
-_cargo() {
+__cargo() {
 	local cur prev words cword
 	_get_comp_words_by_ref cur prev words cword
 
@@ -156,7 +156,7 @@ _cargo() {
 	return 0
 }
 
-complete -F _cargo cargo
+complete -F __cargo cargo
 
 __cargo_commands=$(cargo --list 2> /dev/null | awk 'NR>1 {print $1}')