partial-merge: add support for `.args` config (`$local` etc.) It will be useful to be able to define custom command-line arguments per partial merge tool just like we have for regular merge tools. In particular, I expect the same binary to handle multiple languages, so it will be useful to be able to pass some argument indicating the language, or perhaps simply an argument defining a regex that's used for finding lines to merge as a sorted set. Differential Revision: https://phab.mercurial-scm.org/D12383

--- a/mercurial/configitems.py	Tue Jan 18 13:05:21 2022 -0800
+++ b/mercurial/configitems.py	Thu Mar 17 11:19:06 2022 -0700
@@ -1601,6 +1601,14 @@
     experimental=True,
 )
 coreconfigitem(
+    b'partial-merge-tools',
+    br'.*\.args',
+    default=b"$local $base $other",
+    generic=True,
+    priority=-1,
+    experimental=True,
+)
+coreconfigitem(
     b'merge-tools',
     b'.*',
     default=None,