Add support for html-beautify (#2788)

* Add support for html-beautify
* Add html-beautify to the list of supported tools
* Update docs

autoload/ale/fix/registry.vim

@@ -350,6 +350,11 @@ let s:default_registry = {
 \       'suggested_filetypes': ['nix'],
 \       'description': 'A formatter for Nix code',
 \   },
+\   'html-beautify': {
+\       'function': 'ale#fixers#html_beautify#Fix',
+\       'suggested_filetypes': ['html', 'htmldjango'],
+\       'description': 'Fix HTML files with html-beautify.',
+\   },
 \}
 
 " Reset the function registry to the default entries.

autoload/ale/fixers/html_beautify.vim

@@ -0,0 +1,21 @@
+" Author: WhyNotHugo <hugo@barrera.io>
+" Description: Lint HTML files with html-beautify.
+"
+call ale#Set('html_beautify_executable', 'html-beautify')
+call ale#Set('html_beautify_use_global', get(g:, 'ale_use_global_executables', 0))
+call ale#Set('html_beautify_options', '')
+call ale#Set('html_beautify_change_directory', 1)
+
+function! ale#fixers#html_beautify#Fix(buffer) abort
+    let l:executable = ale#python#FindExecutable(
+    \   a:buffer,
+    \   'html_beautify',
+    \   ['html-beautify']
+    \)
+
+    let l:options = ale#Var(a:buffer, 'html_beautify_options')
+
+    return {
+    \   'command': ale#Escape(l:executable). ' ' . l:options . ' -',
+    \}
+endfunction