Added ocamllsp (#3595)

* Added ocamllsp

* Update ordering in docs to be alphabetical

* Updated expected result in test

autoload/ale/handlers/ocamllsp.vim

@@ -0,0 +1,23 @@
+" Author: Risto Stevcev <me@risto.codes>
+" Description: Handlers for the official OCaml language server
+
+function! ale#handlers#ocamllsp#GetExecutable(buffer) abort
+    return 'ocamllsp'
+endfunction
+
+function! ale#handlers#ocamllsp#GetCommand(buffer) abort
+    let l:executable = ale#handlers#ocamllsp#GetExecutable(a:buffer)
+    let l:ocaml_ocamllsp_use_opam = ale#Var(a:buffer, 'ocaml_ocamllsp_use_opam')
+
+    return l:ocaml_ocamllsp_use_opam ? 'opam config exec -- ' . l:executable : l:executable
+endfunction
+
+function! ale#handlers#ocamllsp#GetLanguage(buffer) abort
+    return getbufvar(a:buffer, '&filetype')
+endfunction
+
+function! ale#handlers#ocamllsp#GetProjectRoot(buffer) abort
+    let l:dune_project_file = ale#path#FindNearestFile(a:buffer, 'dune-project')
+
+    return !empty(l:dune_project_file) ? fnamemodify(l:dune_project_file, ':h') : ''
+endfunction