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

ale_linters/c3/c3lsp.vim

@@ -0,0 +1,22 @@
+" Author: Koni Marti <koni.marti@gmail.com>
+" Description: A Language Server implementation for C3
+
+call ale#Set('c3_c3lsp_executable', 'c3lsp')
+call ale#Set('c3_c3lsp_options', '')
+call ale#Set('c3_c3lsp_init_options', {})
+
+function! ale_linters#c3#c3lsp#GetCommand(buffer) abort
+    let l:executable = ale#Var(a:buffer, 'c3_c3lsp_executable')
+
+    return ale#Escape(l:executable) . ale#Pad(ale#Var(a:buffer, 'c3_c3lsp_options'))
+endfunction
+
+
+call ale#linter#Define('c3', {
+\   'name': 'c3lsp',
+\   'lsp': 'stdio',
+\   'executable': {b -> ale#Var(b, 'c3_c3lsp_executable')},
+\   'command': function('ale_linters#c3#c3lsp#GetCommand'),
+\   'project_root': function('ale#handlers#c3lsp#GetProjectRoot'),
+\   'lsp_config': {b -> ale#handlers#c3lsp#GetInitOpts(b, 'c3_c3lsp_init_options')},
+\})