feat: config option to customize floating window title (#482)

* replace cwd path in actual path

* move get_title to utils

* add documentation

* rename

* add method doc

* add comment

* fallback to 0 for winid

* add missing property definition for relative_win_title

* only replace when at the start of the path

* simplify

* minor change

* add entry point to customize floating window title for oil-buffer

* remove config parameter

* cleanup

* add documentation

* move get_win_title to top and pass winid as parameter

* add get_win_title to type definition for oil.setup

* remove empty line

* adjust comment

---------

Co-authored-by: Philipp Oeschger <philippoeschger@Philipps-Air.fritz.box>

doc/oil.txt

@@ -142,6 +142,8 @@ CONFIG                                                                *oil-confi
         win_options = {
           winblend = 0,
         },
+        -- optionally override the oil buffers window title with custom function: fun(path: string): string
+        get_win_title = nil,
         -- preview_split: Split direction: "auto", "left", "right", "above", "below".
         preview_split = "auto",
         -- This is the config that will be passed to nvim_open_win.