Log Message:
xorgproto: update to 2021.2.

This release is mostly all about keysyms. Some additions to Vietnamese and
Hangul but the big set of commits here is catching up with several years of
Linux kernel releases.

The kernel's evdev interface has semantic keycodes (e.g. KEY_ESC is what
you'd expect). Beyond the normal range expected to change with different
layouts there are many keycodes that should only ever do one thing.
For example, KEY_ONSCREEN_KEYBOARD should display the OSK regardless of
layout). In the past, we've added these keysyms on a as-requested basis.

We now have a reserved subrange in the already reserved range for XF86Foo
keysyms. Within that range, keysyms map directly to their evdev
counterparts, making future updates easier. The above example
KEY_ONSCREEN_KEYBOARD now has a XF86OnScreenKeyboard keysym.
The header file follows a strict convention to make this range
machine-readable, xkeyboard-config can make use of this to
make those keysyms available by default. Note that almost all keys are
outside the X keycode range so very little will change under X.

Note that most keys exist on selected devices only so the practial use is
quite limited. But those keysyms are available through normal XKB
configuration so users can re-map existing keys where needed.

Aside from those, a bit of misc cleanup work. Many thanks to all
contributors.