gh-151886: Add tkinter Misc.tk_appname, tk_useinputmethods and tk_caret (GH-151887)

gh-151886: Add tkinter Misc.tk_appname, tk_useinputmethods and tk_caret (GH-151887)

Wrap three long-standing Tk commands that had no tkinter wrapper:

* Misc.tk_appname() queries or sets the name used to communicate with the
  application through the send command (Tk 8.5).
* Misc.tk_useinputmethods() queries or sets whether Tk uses the X Input
  Methods (XIM) for filtering events (Tk 8.5).
* Misc.tk_caret() sets or queries the per-display caret location used for
  accessibility and for placing the input method window (Tk 8.5).

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>