Fix the values and documentation of 'printable-chars' table

Fix the values and documentation of 'printable-chars' table

* src/character.c (syms_of_character) <printable-chars>: Doc fix.

* lisp/international/characters.el (printable-chars): Fix values
for non-ASCII characters.

* doc/lispref/nonascii.texi (Character Properties): Add
cross-reference for what is a printable character.
* doc/lispref/display.texi (Usual Display):
* doc/lispref/searching.texi (Char Classes): Add indexing.
(Bug#76611)

(cherry picked from commit 68a37760dec83a8126b03bcacc60a96644a6831f)