Removed syntastic and replaced it with ale

Read more here:
https://github.com/w0rp/ale

sources_non_forked/ale/ale_linters/fish/fish.vim

@@ -0,0 +1,67 @@
+" Author: Niraj Thapaliya - https://github.com/nthapaliya
+" Description: Lints fish files using fish -n
+
+function! ale_linters#fish#fish#Handle(buffer, lines) abort
+    " Matches patterns such as:
+    "
+    " home/.config/fish/functions/foo.fish (line 1): Missing end to balance this function definition
+    " function foo
+    " ^
+    "
+    " OR, patterns such as:
+    "
+    " Unsupported use of '||'. In fish, please use 'COMMAND; or COMMAND'.
+    " /tmp/vLz620o/258/test.fish (line 2): if set -q SSH_CLIENT || set -q SSH_TTY
+    "                                                            ^
+    "
+    " fish -n can return errors in either format.
+    let l:pattern = '^\(.* (line \(\d\+\)): \)\(.*\)$'
+    let l:column_pattern = '^ *\^'
+    let l:output = []
+    let l:column_offset = 0
+    let l:last_line_with_message = ''
+
+    for l:line in a:lines
+        " Look for error lines first.
+        let l:match = matchlist(l:line, l:pattern)
+
+        if !empty(l:match)
+            if !empty(l:last_line_with_message)
+                let l:text = l:last_line_with_message
+            else
+                let l:text = l:match[3]
+            endif
+
+            let l:column_offset = len(l:match[1])
+
+            let l:last_line_with_message = ''
+            call add(l:output, {
+            \  'col': 0,
+            \  'lnum': str2nr(l:match[2]),
+            \  'text': l:text,
+            \})
+        else
+            " Look for column markers like '   ^' second.
+            " The column index will be set according to how long the line is.
+            let l:column_match = matchstr(l:line, l:column_pattern)
+
+            if !empty(l:column_match) && !empty(l:output)
+                let l:output[-1].col = len(l:column_match) - l:column_offset
+                let l:last_line_with_message = ''
+            else
+                let l:last_line_with_message = l:line
+                let l:column_offset = 0
+            endif
+        endif
+    endfor
+
+    return l:output
+endfunction
+
+call ale#linter#Define('fish', {
+\   'name': 'fish',
+\   'output_stream': 'stderr',
+\   'executable': 'fish',
+\   'command': 'fish -n %t',
+\   'callback': 'ale_linters#fish#fish#Handle',
+\})