Migrate from the silver searcher to ripgrep

vim/settings/ctrlp.vim

@@ -1,12 +1,12 @@
 if exists("g:ctrlp_user_command")
   unlet g:ctrlp_user_command
 endif
-if executable('ag')
-  " Use ag in CtrlP for listing files. Lightning fast and respects .gitignore
-  let g:ctrlp_user_command =
-    \ 'ag %s --files-with-matches -g "" --ignore "\.git$\|\.hg$\|\.svn$"'
 
-  " ag is fast enough that CtrlP doesn't need to cache
+if executable('rg')
+  " Use rg in CtrlP for listing files. Lightning fast and respects .gitignore
+  let g:ctrlp_user_command = 'rg --files --smart-case %s'
+
+  " rg is fast enough that CtrlP doesn't need to cache
   let g:ctrlp_use_caching = 0
 else
   " Fall back to using git ls-files if Ag is not available