minibuffer-allow-text-properties can be buffer-local and affects completions

minibuffer-allow-text-properties can be buffer-local and affects completions

* doc/lispref/minibuf.texi (Text from Minibuffer): Mention that
minibuffer-allow-text-properties can be let-bound or buffer-local
in the minibuffer.  Correct the description of
minibuffer-allow-text-properties to explain what it did
even before applying code changes in this patch.
Remove wrong example for read-no-blanks-input.

* lisp/imenu.el (imenu--completion-buffer): Set buffer-local
minibuffer-allow-text-properties to t.
(imenu--completion-buffer): Get text property 'imenu-choice'.
(imenu--flatten-index-alist): Propertize annotation
with text property 'imenu-choice'.

* lisp/simple.el (choose-completion): Don't remove text properties
from the returned completion string since the value of
minibuffer-allow-text-properties is already respected
in completion--replace.

* src/minibuf.c (read_minibuf): Preserve text properties not only
when allow_props is non-nil but also in case when
minibuffer_allow_text_properties is non-nil.
(Fread_from_minibuffer): Mention in the docstring that
minibuffer-allow-text-properties can be buffer-local in the minibuffer.
(minibuffer-allow-text-properties): Improve docstring to describe
when text properties are discarded.

https://lists.gnu.org/archive/html/emacs-devel/2024-05/msg00949.html