Add tkinter wrappers for the tk appname, tk useinputmethods and tk caret commands

[serhiy-storchaka]

A few long-standing Tk commands have no tkinter wrapper and are currently reachable only through tk.call().

• tk appname (since Tk 8.5) queries or sets the name used to communicate with the application through the send command.
• tk useinputmethods (since Tk 8.5) queries or sets whether Tk uses the X Input Methods (XIM) for filtering events.
• tk caret (since Tk 8.5) sets or queries the per-display caret location used for accessibility and for placing the input method (XIM or IME) window.

I propose to add the corresponding Misc.tk_appname(), Misc.tk_useinputmethods() and Misc.tk_caret() methods.

Linked PRs

• gh-151886: Add tkinter Misc.tk_appname, tk_useinputmethods and tk_caret #151887