console.lua: add a keep_open flag to mp.input

With input.select this allows building nested submenus without the
flicker of console quickly closing and reopening, and also doing
multiple selections, to e.g. cycle through different values of a
property, or increase a property multiple times.

With input.get this is used to change the default behavior to closing by
default on submit. It was argued by avih that this is more useful, and
indeed Github code search shows that everybody is calling
input.terminate() unconditionally on submit, so the impact of the change
should be low, and restoring the old behavior is as easy as passing
keep_open = true, which is just ignored in older mpv versions.

DOCS/interface-changes/mp.input.txt

@@ -0,0 +1,2 @@
+add `keep_open` flag to `mp.input.get()` and `mp.input.select()`
+`mp.input.get()` now closes automatically on submit, pass `keep_open = true` to restore the old behavior

DOCS/man/lua.rst

@@ -926,9 +926,10 @@ REPL.
 
     ``submit``
         A callback invoked when the user presses Enter. The first argument is
-        the text in the console. You can close the console from within the
-        callback by calling ``input.terminate()``. If you don't, the console
-        stays open and the user can input more text.
+        the text in the console.
+
+    ``keep_open``
+        Whether to keep the console open on submit. Defaults to ``false``.
 
     ``opened``
         A callback invoked when the console is shown. This can be used to
@@ -1013,9 +1014,10 @@ REPL.
 
     ``submit``
         The callback invoked when the user presses Enter. The first argument is
-        the 1-based index of the selected item. Unlike with ``input.get()``, the
-        console is automatically closed on submit without having to call
-        ``input.terminate()``.
+        the 1-based index of the selected item.
+
+    ``keep_open``
+        Whether to keep the console open on submit. Defaults to ``false``.
 
     Example:
 

player/lua/console.lua

@@ -104,6 +104,7 @@ local dont_bind_up_down = false
 local overlay = mp.create_osd_overlay('ass-events')
 local global_margins = { t = 0, b = 0 }
 local input_caller
+local keep_open = false
 
 local completion_buffer = {}
 local selected_completion_index
@@ -1093,7 +1094,6 @@ local function submit()
             mp.commandv('script-message-to', input_caller, 'input-event', 'submit',
                         utils.format_json({matches[selected_match].index}))
         end
-        set_active(false)
     elseif input_caller then
         mp.commandv('script-message-to', input_caller, 'input-event', 'submit',
                     utils.format_json({line}))
@@ -1116,7 +1116,11 @@ local function submit()
         history_add(line)
     end
 
-    clear()
+    if input_caller and not keep_open then
+        set_active(false)
+    elseif not selectable_items then
+        clear()
+    end
 end
 
 local function determine_hovered_item()
@@ -2107,6 +2111,7 @@ mp.register_script_message('get-input', function (script_name, args)
     line = args.default_text or ''
     cursor = args.cursor_position or line:len() + 1
     id = args.id or script_name .. prompt
+    keep_open = args.keep_open
     dont_bind_up_down = args.dont_bind_up_down
     if histories[id] == nil then
         histories[id] = {}

player/lua/stats.lua

@@ -1562,7 +1562,6 @@ local function filter_bindings()
                 display_timer:resume()
             end
         end,
-        submit = input.terminate,
         closed = function ()
             searched_text = nil
             if display_timer:is_enabled() then