Remove legacy keycodes, part 2 (#18660)

* `KC_SYSREQ` -> `KC_SYRQ`

And one `KC_ALT_ERASE` -> `KC_ERAS`

* `KC_NONUS_BSLASH` -> `KC_NUBS`

* `KC_NUMLOCK` -> `KC_NUM`

* `KC_CLCK` -> `KC_CAPS`

* `KC_SCROLLLOCK` -> `KC_SCRL`

* `KC_LBRACKET` -> `KC_LBRC`

* `KC_RBRACKET` -> `KC_RBRC`

* `KC_CAPSLOCK` -> `KC_CAPS`

keyboards/bpiphany/kitten_paw/keymaps/ickerwx/keymap.c

@@ -136,7 +136,7 @@ bool process_record_user(uint16_t keycode, keyrecord_t *record) {
     if (layer == PROG2) {
          if (keycode >= KC_A && keycode <= KC_EXSEL && \
              !(  // do not send LSFT + these keycodes, they are needed for emulating the US layout
-                 keycode == KC_NONUS_BSLASH ||
+                 keycode == KC_NUBS ||
                  keycode == KC_RBRC ||
                  keycode == KC_BSLS ||
                  keycode == KC_GRV