nodemap: move the main switch to the `format` section

The config to enable persistent nodemap is now `format.use-persistent-nodemap`.
However the option remain marked as experimental because it only improve
performance for people using the rust extensions.

Differential Revision: https://phab.mercurial-scm.org/D8419

mercurial/configitems.py

@@ -675,9 +675,6 b' coreconfigitem('
     b'experimental', b'rust.index', default=False,
 )
 coreconfigitem(
-    b'experimental', b'exp-persistent-nodemap', default=False,
-)
-coreconfigitem(
     b'experimental', b'exp-persistent-nodemap.mmap', default=True,
 )
 coreconfigitem(
@@ -787,6 +784,9 b' coreconfigitem('
     b'format', b'usestore', default=True,
 )
 coreconfigitem(
+    b'format', b'use-persistent-nodemap', default=False, experimental=True
+)
+coreconfigitem(
     b'format',
     b'exp-use-copies-side-data-changeset',
     default=False,

mercurial/localrepo.py

@@ -3664,7 +3664,7 b' def newreporequirements(ui, createopts):'
     if ui.configbool(b'format', b'bookmarks-in-store'):
         requirements.add(bookmarks.BOOKMARKS_IN_STORE_REQUIREMENT)
 
-    if ui.configbool(b'experimental', b'exp-persistent-nodemap'):
+    if ui.configbool(b'format', b'use-persistent-nodemap'):
         requirements.add(NODEMAP_REQUIREMENT)
 
     return requirements

tests/test-persistent-nodemap.t

@@ -3,8 +3,8 b' Test the persistent on-disk nodemap'
 ===================================
 
   $ cat << EOF >> $HGRCPATH
-  > [experimental]
-  > exp-persistent-nodemap=yes
+  > [format]
+  > use-persistent-nodemap=yes
   > [devel]
   > persistent-nodemap=yes
   > EOF