Allow to set title in winopts for widgets

[lervag]

Problem Statement

I want to apply some global window option configuration for widgets. The main intent is to make it more clear which window I have opened and to have a streamlined UI (I customize other types of windows as well). In particular, I want to put the title of the window into the border.

Possible Solutions

I know I can do this by using the .build mechanism, but then I will need to use this more verbose mechanism for every mapping. And there is already support for passing window options such as the border:

nvim-dap/lua/dap/ui.lua

Lines 18 to 19 in 7c1d47c

	elseif k == 'border' then
	api.nvim_win_set_config(win, {[k]=v})

I propose adding an additional:

    elseif k == 'title' then
      api.nvim_win_set_config(win, {[k]=v})

Of course, this could possibly be improved e.g. by doing something like (pseudocode):

elseif k in valid_options then

where valid_options was a list of the valid floating window options (see :help nvim_open_win for the list of options).

Considered Alternatives

No response

[lervag]

Closed by #974.