resolve: add commands.resolve.mark-check=abort to tweakdefaults

Differential Revision: https://phab.mercurial-scm.org/D4072

mercurial/ui.py

@@ -67,6 +67,9 b' status.relative = yes'
 update.check = noconflict
 # Show conflicts information in `hg status`
 status.verbose = True
+# Refuse to perform `hg resolve --mark` on files that still have conflict
+# markers
+resolve.mark-check = abort
 
 [diff]
 git = 1