DNA: warn about old versioning being incomplete

Also sync variable names w/ D4342

Fix DNA struct member versioning logic

Possible error changing names which are shared between structs.
While the problem doesn't occur at the moment, avoid future problems.

Cleanup: sync minor changes from D4342

Use naming conventions from the patch so they match when it's applied.

UI: impossible to activate RMB menu on menu items

Right clicking on a menu item now closes it's sub-menus and opens
the button's context menu.

This is needed for adding them to the quick favourites menu.

Resolves T58729, T61015.

Fix T60905: Crash using smooth tool

Tools were relying on gizmos drawing to initialize their gizmos,
now tool gizmos are initialized immediately.

Fix T58090: Selected curve vertex should stand out

D4002 by @slumber w/ edits.

Use text colors, blending to background if they don't contrast.

makesdna: correct function docs

Also use doxy sections & remove parens from return values.

ctodata: make stripping the last byte optional

Fix T56665: Assert when selecting object

Selecting object w/ a different mode missed refreshing the screen
areas current tool.

UI: add symmetrize to armature menu

Was lost on menu reorganization,
minor tweaks to make it match the context menu.