Use explicit scope in all ale_linters

vint -s is now clean

ale_linters/html/tidy.vim

@@ -12,10 +12,9 @@ let g:ale_html_tidy_executable = get(g:, 'ale_html_tidy_executable', 'tidy')
 let g:ale_html_tidy_args = get(g:, 'ale_html_tidy_args', '-q -e -language en')
 
 function! ale_linters#html#tidy#GetCommand(buffer) abort
-
     " Specify file encoding in options
     " (Idea taken from https://github.com/scrooloose/syntastic/blob/master/syntax_checkers/html/tidy.vim)
-    let file_encoding = get({
+    let l:file_encoding = get({
     \   'ascii':        '-ascii',
     \   'big5':         '-big5',
     \   'cp1252':       '-win1252',
@@ -33,7 +32,7 @@ function! ale_linters#html#tidy#GetCommand(buffer) abort
     return printf('%s %s %s -',
     \   g:ale_html_tidy_executable,
     \   g:ale_html_tidy_args,
-    \   file_encoding
+    \   l:file_encoding
     \ )
 endfunction
 
@@ -41,34 +40,34 @@ function! ale_linters#html#tidy#Handle(buffer, lines) abort
     " Matches patterns lines like the following:
     " line 7 column 5 - Warning: missing </title> before </head>
 
-    let pattern = '^line \(\d\+\) column \(\d\+\) - \(Warning\|Error\): \(.\+\)$'
-    let output = []
+    let l:pattern = '^line \(\d\+\) column \(\d\+\) - \(Warning\|Error\): \(.\+\)$'
+    let l:output = []
 
-    for line in a:lines
-        let match = matchlist(line, pattern)
+    for l:line in a:lines
+        let l:match = matchlist(l:line, l:pattern)
 
-        if len(match) == 0
+        if len(l:match) == 0
             continue
         endif
 
-        let line = match[1] + 0
-        let col = match[2] + 0
-        let type = match[3] ==# 'Error' ? 'E' : 'W'
-        let text = match[4]
+        let l:line = l:match[1] + 0
+        let l:col = l:match[2] + 0
+        let l:type = l:match[3] ==# 'Error' ? 'E' : 'W'
+        let l:text = l:match[4]
 
         " vcol is Needed to indicate that the column is a character.
-        call add(output, {
+        call add(l:output, {
         \   'bufnr': a:buffer,
-        \   'lnum': line,
+        \   'lnum': l:line,
         \   'vcol': 0,
-        \   'col': col,
-        \   'text': text,
-        \   'type': type,
+        \   'col': l:col,
+        \   'text': l:text,
+        \   'type': l:type,
         \   'nr': -1,
         \})
     endfor
 
-    return output
+    return l:output
 endfunction
 
 call ale#linter#Define('html', {