#3599 - Use ale_root instead of ale_lsp_root

The `ale_lsp_root` setting is now deprecated, and `ale_root` should be
used instead. The setting will be used for both setting the root easily
for LSP linters, and for running other linters over whole projects.

test/test_linter_defintion_processing.vader

@@ -1,9 +1,9 @@
 Before:
-  Save g:ale_lsp_root
-  Save b:ale_lsp_root
+  Save g:ale_root
+  Save b:ale_root
 
-  let g:ale_lsp_root = {}
-  unlet! b:ale_lsp_root
+  let g:ale_root = {}
+  unlet! b:ale_root
 
   let g:linter = {}