[enhancement] add node_modules support for stylelint & htmlhint (#226)

* Add node_modules support for stylelint

* add node_modules support for htmlhint

* fix stdin

* update doc about stylelint & htmlhint

ale_linters/css/stylelint.vim

@@ -1,8 +1,31 @@
 " Author: diartyz <diartyz@gmail.com>
 
+let g:ale_css_stylelint_executable =
+\   get(g:, 'ale_css_stylelint_executable', 'stylelint')
+
+let g:ale_css_stylelint_use_global =
+\   get(g:, 'ale_css_stylelint_use_global', 0)
+
+function! ale_linters#css#stylelint#GetExecutable(buffer) abort
+    if g:ale_css_stylelint_use_global
+        return g:ale_css_stylelint_executable
+    endif
+
+    return ale#util#ResolveLocalPath(
+    \   a:buffer,
+    \   'node_modules/.bin/stylelint',
+    \   g:ale_css_stylelint_executable
+    \)
+endfunction
+
+function! ale_linters#css#stylelint#GetCommand(buffer) abort
+    return ale_linters#css#stylelint#GetExecutable(a:buffer)
+    \   . ' --stdin-filename %s'
+endfunction
+
 call ale#linter#Define('css', {
 \   'name': 'stylelint',
-\   'executable': 'stylelint',
-\   'command': g:ale#util#stdin_wrapper . ' .css stylelint',
+\   'executable_callback': 'ale_linters#css#stylelint#GetExecutable',
+\   'command_callback': 'ale_linters#css#stylelint#GetCommand',
 \   'callback': 'ale#handlers#HandleStyleLintFormat',
 \})