Make c-ts-mode-set-style's effect local (bug#61245)

Make c-ts-mode-set-style's effect local (bug#61245)

Now c-ts-mode-set-style's effect is local, and there is a new function
c-ts-mode-set-global-style that changes the global setting.

* lisp/progmodes/c-ts-mode.el:
(c-ts-mode--indent-style-setter): Use c-ts-mode-set-style.
(c-ts-mode-indent-style)
(c-ts-mode--prompt-for-style): Minor change in docstring.
(c-ts-mode-set-global-style): New function (from c-ts-mode-set-style).
(c-ts-mode-set-local-style): Remove function (became c-ts-mode-set-style).
(c-ts-mode-set-style): Renamed from c-ts-mode-set-local-style.
* test/lisp/progmodes/c-ts-mode-resources/indent-bsd.erts:
* test/lisp/progmodes/c-ts-mode-resources/indent.erts: Use
c-ts-mode-set-style.