new feature recommendation: set-bookmark and clear-bookmark

[vasarhelyi]

PsPad editor has a very nice feature of using bookmarks with Alt and arrows. For this, first of all, "toggle bookmark" needs to be supplemented with "set bookmark" and "clear bookmark" separately, secondly, key bindings has to be changed but this can be user defined. I created (but did not check) a patch recommendation for this, would you find it useful?

set-and-clear-bookmarks.patch.txt