Elm local install support (#915)

* Add Elm support for npm local installation

doc/ale-elm.txt

@@ -28,5 +28,23 @@ g:ale_elm_format_options                             *g:ale_elm_format_options*
 
   This variable can be set to pass additional options to elm-format.
 
+===============================================================================
+elm-make                                                         *ale-elm-make*
+
+g:ale_elm_make_executable                           *g:ale_elm_make_executable*
+                                                    *b:ale_elm_make_executable*
+  Type: |String|
+  Default: `'elm-make'`
+  
+  See |ale-integrations-local-executables|
+  
+  
+g:ale_elm_make_use_global                           *g:ale_elm_make_use_global*
+                                                    *b:ale_elm_make_use_global*                                         
+  Type: |Number|
+  Default: `0`
+
+  See |ale-integrations-local-executables|
+
 ===============================================================================
   vim:tw=78:ts=2:sts=2:sw=2:ft=help:norl:

doc/ale.txt

@@ -217,7 +217,7 @@ Notes:
 * Dart: `dartanalyzer`
 * Dockerfile: `hadolint`
 * Elixir: `credo`, `dogma`!!
-* Elm: `elm-make, elm-format`
+* Elm: `elm-format, elm-make`
 * Erb: `erb`, `erubis`
 * Erlang: `erlc`, `SyntaxErl`
 * Fortran: `gcc`