sysutils/xplr: update to 0.15.0

Changes & fixes:
-Added CustomContent as layout option that can be used to render custom
paragraphs, lists and tables. Both static and dynamic.
-Added support for optionally defining custom layouts for different modes.
-Added xplr.config.general.focus_selection_ui to highlight selected files
under focus differently than files under focus that are not selected.
-Added PopModeKeepingInputBuffer, and SwitchMode alternatives to allow
switching to different modes without resetting the input buffer.
-Removed config field from CallLuaArg as it's already available globally
as xplr.config.
-Fixed a bug which caused xplr to misbehave when used with specific tools and
environment (e.g. neovim, fzf, zsh4humans etc.).
-Recover mode will be disabled by default.
i.e. xplr.config.general.disable_recover_mode has been deprecated. Use
xplr.config.general.enable_recover_mode instead.
Library users please refer to the latest API docs and examples.
-New homepage: https://xplr.dev

(pin)