emacs-27 7cafbbe: Fix describe-variable on values with circular syntax (Bug#39805)

[Noam Postavsky]

branch: emacs-27
commit 7cafbbe96434ef616abfef364d82f7250bffc1ed
Author: Noam Postavsky <address@hidden>
Commit: Noam Postavsky <address@hidden>

    Fix describe-variable on values with circular syntax (Bug#39805)
    
    * lisp/help-fns.el (describe-variable): Set syntax tables before
    calling pp-buffer.
---
 lisp/help-fns.el | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/lisp/help-fns.el b/lisp/help-fns.el
index 0e2ae6b..1be8e0a 100644
--- a/lisp/help-fns.el
+++ b/lisp/help-fns.el
@@ -1000,6 +1000,8 @@ it is displayed along with the global value."
                    (terpri)
                     (let ((buf (current-buffer)))
                       (with-temp-buffer
+                        (lisp-mode-variables nil)
+                        (set-syntax-table emacs-lisp-mode-syntax-table)
                         (insert print-rep)
                         (pp-buffer)
                         (let ((pp-buffer (current-buffer)))