* Add standard ALGR defition, remove (re)definitions from language files
* Use ALGR(kc) consistently in ALTGR(kc) aliases
* Non-Nordic keymaps should not use NO_ALGR
* Add standard KC_ALGR definition
* Update docs with ALGR and KC_ALGR
* Update SS_ALGR and ALGR_T aliases
* Clean up SEND_STRING keycodes and add media keys
* Remove stray define
* Add missing SEND_STRING keycodes for completeness
Also, add KC_EJCT to the keycode references