bug#30786: Save text properties in desktop

[Juri Linkov]

Why does desktop.el not save text properties?
Maybe for some historical reasons?
This is required for bug#22479.
I can't find a problem while trying this patch:

diff --git a/lisp/desktop.el b/lisp/desktop.el
index 8bd4465..a7e549f 100644
--- a/lisp/desktop.el
+++ b/lisp/desktop.el
@@ -852,10 +852,7 @@ desktop--v2s
     ((or (numberp value) (null value) (eq t value) (keywordp value))
      (cons 'may value))
     ((stringp value)
-     (let ((copy (copy-sequence value)))
-       (set-text-properties 0 (length copy) nil copy)
-       ;; Get rid of text properties because we cannot read them.
-       (cons 'may copy)))
+     (cons 'may value))
     ((symbolp value)
      (cons 'must value))
     ((vectorp value)