Add support for c3-lsp linter (#4836)

* Add support for c3-lsp linter

Add support for c3-lang with the c3-lsp language server.

Link: http://github.com/pherrymason/c3-lsp
Link: http://c3-lang.org

* fix linter error

* fix: consistent use of the executable name

Consistently use the executable name 'c3lsp' instead of the project name
'c3-lsp'.

* c3lsp: add command line arguments to executable

doc/ale-c3.txt

@@ -0,0 +1,35 @@
+===============================================================================
+ALE C3 Integration                                             *ale-c3-options*
+
+===============================================================================
+c3lsp                                                            *ale-c3-c3lsp*
+
+g:ale_c3_c3lsp_executable                           *g:ale_c3_c3lsp_executable*
+                                                    *b:ale_c3_c3lsp_executable*
+  Type: |String|
+  Default: `c3lsp`
+
+  This variable can be changed to set the path to c3lsp executable.
+
+
+g:ale_c3_c3lsp_options                                 *g:ale_c3_c3lsp_options*
+                                                       *b:ale_c3_c3lsp_options*
+
+  Type: |String|
+  Default: `''`
+
+  Add command line options to the c3lsp executable. This is useful to specify
+  the path to the C3 standard library with '-stdlib-path=<path>'.
+
+
+g:ale_c3_c3lsp_init_options                       *g:ale_c3_c3lsp_init_options*
+                                                  *b:ale_c3_c3lsp_init_options*
+  Type: |Dictionary|
+  Default: `{}`
+
+  Dictionary containing configuration settings that will be passed to the
+  language server.
+
+
+===============================================================================
+  vim:tw=78:ts=2:sts=2:sw=2:ft=help:norl: