Use explicit scope in all ale_linters

vint -s is now clean

ale_linters/scss/scsslint.vim

@@ -11,11 +11,11 @@ function! ale_linters#scss#scsslint#Handle(buffer, lines)
     " Matches patterns like the following:
     "
     " test.scss:2:1 [W] Indentation: Line should be indented 2 spaces, but was indented 4 spaces
-    let pattern = '^.*:\(\d\+\):\(\d*\) \[\([^\]]\+\)\] \(.\+\)$'
-    let output = []
+    let l:pattern = '^.*:\(\d\+\):\(\d*\) \[\([^\]]\+\)\] \(.\+\)$'
+    let l:output = []
 
-    for line in a:lines
-        let l:match = matchlist(line, pattern)
+    for l:line in a:lines
+        let l:match = matchlist(l:line, l:pattern)
 
         if len(l:match) == 0
             continue
@@ -27,7 +27,7 @@ function! ale_linters#scss#scsslint#Handle(buffer, lines)
         endif
 
         " vcol is needed to indicate that the column is a character
-        call add(output, {
+        call add(l:output, {
         \   'bufnr': a:buffer,
         \   'lnum': l:match[1] + 0,
         \   'vcol': 0,
@@ -38,7 +38,7 @@ function! ale_linters#scss#scsslint#Handle(buffer, lines)
         \})
     endfor
 
-    return output
+    return l:output
 endfunction
 
 call ale#linter#Define('scss', {