Add support for purescript language server (#2572)

* Add support for purescript language server
* Update naming
* Add purescript language server tests

doc/ale-purescript.txt

@@ -0,0 +1,33 @@
+===============================================================================
+ALE PureScript Integration                             *ale-purescript-options*
+
+
+===============================================================================
+purescript-language-server                     *ale-purescript-language-server*
+
+PureScript Language Server
+  (https://github.com/nwolverson/purescript-language-server)
+
+g:ale_purescript_ls_executable                 g:ale_purescript_ls_executable
+                                               b:ale_purescript_ls_executable
+  Type: |String|
+  Default: `'purescript-language-server'`
+
+  PureScript language server executable.
+
+g:ale_purescript_ls_config                         g:ale_purescript_ls_config
+                                                   b:ale_purescript_ls_config
+  Type: |Dictionary|
+  Default: `{}`
+
+  Dictionary containing configuration settings that will be passed to the
+  language server. For example, with a spago project:
+		{
+		\  'purescript': {
+		\    'addSpagoSources': v:true,
+		\    'addNpmPath': v:true,
+		\    'buildCommand': 'spago build -- --json-errors'
+		\  }
+		\}
+===============================================================================
+  vim:tw=78:ts=2:sts=2:sw=2:ft=help:norl:

doc/ale-supported-languages-and-tools.txt

@@ -338,6 +338,8 @@ Notes:
   * `languageserver`
   * `puppet`
   * `puppet-lint`
+* PureScript
+  * `purescript-language-server`
 * Python
   * `autopep8`
   * `bandit`

doc/ale.txt

@@ -2176,6 +2176,8 @@ documented in additional help files.
     puppet................................|ale-puppet-puppet|
     puppetlint............................|ale-puppet-puppetlint|
     puppet-languageserver.................|ale-puppet-languageserver|
+  purescript..............................|ale-purescript-options|
+    purescript-language-server............|ale-purescript-language-server|
   pyrex (cython)..........................|ale-pyrex-options|
     cython................................|ale-pyrex-cython|
   python..................................|ale-python-options|