feat: Add follow_cursor and restore_location

New lua API function: follow_cursor (supports opts.focus_outline).
This sets location in outline to match location in code.

New keymap: restore_location (C-g) by default.
This provides the same functionality as follow_cursor.

I've also refactored other lua API functions for consistency of using
`opts.focus_outline`. If opts is not provided, focus_outline is
defaulted to true. To change this behaviour, set it to false.

lua/symbols-outline/providers/init.lua

@@ -21,13 +21,13 @@ function M.has_provider()
 end
 
 ---@param on_symbols function
-function M.request_symbols(on_symbols)
+function M.request_symbols(on_symbols, opts)
   for _, value in ipairs(providers) do
     local provider = require(value)
     if provider.should_use_provider(0) then
       _G._symbols_outline_current_provider = provider
       _G._symbols_outline_current_provider.name = value
-      provider.request_symbols(on_symbols)
+      provider.request_symbols(on_symbols, opts)
       break
     end
   end