Fix #510 Support checking LESS files with stylelint

doc/ale-less.txt

@@ -35,5 +35,32 @@ prettier                                                    *ale-less-prettier*
 See |ale-javascript-prettier| for information about the available options.
 
 
+===============================================================================
+stylelint                                                  *ale-less-stylelint*
+
+g:ale_less_stylelint_executable               *g:ale_less_stylelint_executable*
+                                              *b:ale_less_stylelint_executable*
+  Type: |String|
+  Default: `'stylelint'`
+
+  See |ale-integrations-local-executables|
+
+
+g:ale_less_stylelint_options                     *g:ale_less_stylelint_options*
+                                                 *b:ale_less_stylelint_options*
+  Type: |String|
+  Default: `''`
+
+  This variable can be set to pass additional options to stylelint.
+
+
+g:ale_less_stylelint_use_global               *g:ale_less_stylelint_use_global*
+                                              *b:ale_less_stylelint_use_global*
+  Type: |String|
+  Default: `0`
+
+  See |ale-integrations-local-executables|
+
+
 ===============================================================================
   vim:tw=78:ts=2:sts=2:sw=2:ft=help:norl:

doc/ale.txt

@@ -107,6 +107,7 @@ CONTENTS                                                         *ale-contents*
     less..................................|ale-less-options|
       lessc...............................|ale-less-lessc|
       prettier............................|ale-less-prettier|
+      stylelint...........................|ale-less-stylelint|
     llvm..................................|ale-llvm-options|
       llc.................................|ale-llvm-llc|
     lua...................................|ale-lua-options|
@@ -298,7 +299,7 @@ Notes:
 * JSON: `jsonlint`, `prettier`
 * Kotlin: `kotlinc`, `ktlint`
 * LaTeX (tex): `chktex`, `lacheck`, `proselint`, `write-good`
-* Less: `lessc`
+* Less: `lessc`, `prettier`, `stylelint`
 * LLVM: `llc`
 * Lua: `luacheck`
 * Mail: `proselint`, `vale`