[3.11] gh-86404: [doc] Fix missing space in idle documentation. (GH-94366) (GH-94369)

This should have been spotted by sphinx-lint, tracked here:

sphinx-contrib/sphinx-lint#39
(cherry picked from commit bc7f6fc)


Co-authored-by: Julien Palard <julien@palard.fr>

Automerge-Triggered-By: GH:JulienPalard

Author: miss-islington

Doc/library/idle.rst

@@ -594,7 +594,7 @@ One may edit pasted code first.
 If one pastes more than one statement into Shell, the result will be a
 :exc:`SyntaxError` when multiple statements are compiled as if they were one.
 
-Lines containing`'RESTART'` mean that the user execution process has been
+Lines containing ``'RESTART'`` mean that the user execution process has been
 re-started.  This occurs when the user execution process has crashed,
 when one requests a restart on the Shell menu, or when one runs code
 in an editor window.