vim/coc: disabling clangd globally in WSL

Issues surrounding calling clangd.exe prevents coc.vim to work with
clangd for Windows based projects.

It could be enabled locally for any other non-Windows project with
:CocLocalConfig.

clangd/coc-clangd#484

vim/coc-settings.json

@@ -1,10 +1,5 @@
 {
   "languageserver": {
-    "clangd": {
-      "command": "clangd",
-      "rootPatterns": ["compile_flags.txt", "compile_commands.json"],
-      "filetypes": ["c", "cc", "cpp", "c++", "objc", "objcpp"]
-    },
     "haskell": {
       "command": "haskell-language-server-wrapper",
       "args": ["--lsp"],