share: move share safe functionality out of experimental The share-safe functionality is complete and all configuration options are implemented. The behavior is well discussed on mailing list and in reviews. Let's unmark this as experimental to solve a chichen and egg issue. Differential Revision: https://phab.mercurial-scm.org/D9823

--- a/mercurial/configitems.py	Fri Jan 15 12:08:07 2021 +0530
+++ b/mercurial/configitems.py	Mon Jan 18 19:16:49 2021 +0530
@@ -1272,9 +1272,8 @@
 )
 coreconfigitem(
     b'format',
-    b'exp-share-safe',
+    b'use-share-safe',
     default=False,
-    experimental=True,
 )
 coreconfigitem(
     b'format',