feat: add find_command option for find_files (#73)

lua/telescope/builtin.lua

@@ -366,7 +366,9 @@ end
 builtin.find_files = function(opts)
   opts = opts or {}
 
-  local find_command = nil
+  local find_command = opts.find_command
+
+  if not find_command then
     if 1 == vim.fn.executable("fd") then
       find_command = { 'fd', '--type', 'f' }
     elseif 1 == vim.fn.executable("fdfind") then
@@ -374,6 +376,7 @@ builtin.find_files = function(opts)
     elseif 1 == vim.fn.executable("rg") then
       find_command = { 'rg', '--files' }
     end
+  end
 
   if not find_command then
     print("You need to install either fd or rg. You can also submit a PR to add support for another file finder :)")