shelve: add --keep to list of allowables

hgext/shelve.py

@@ -1120,6 +1120,7 b' def shelvecmd(ui, repo, *pats, **opts):'
 #       ('date', {'create'}), # ignored for passing '--date "0 0"' in tests
         ('delete', {'delete'}),
         ('edit', {'create'}),
+        ('keep', {'create'}),
         ('list', {'list'}),
         ('message', {'create'}),
         ('name', {'create'}),

tests/test-shelve.t

@@ -933,6 +933,15 b' Test shelve --keep'
 
   $ hg unshelve
   unshelving change 'default'
+  $ hg shelve --keep --list
+  abort: options '--list' and '--keep' may not be used together
+  [255]
+  $ hg shelve --keep --patch
+  abort: options '--patch' and '--keep' may not be used together
+  [255]
+  $ hg shelve --keep --delete
+  abort: options '--delete' and '--keep' may not be used together
+  [255]
   $ hg shelve --keep
   shelved as default
   $ hg diff