improve suggestion for setting username

Summary:
Update instructions to:

- suggest `--user` instead of `--edit`
- edit config via CLI directly without opening an editor

I also noticed that currently, on Windows, trying to open an
editor to edit a config attempts to use `vi` by default, which fails.

Reviewed By: zzl0

Differential Revision: D41062921

fbshipit-source-id: faac2a897a63939d7fb03d3ab6d11851e951c05f

eden/scm/edenscm/ui.py

@@ -600,7 +600,9 @@ class ui(object):
         if not user:
             raise error.Abort(
                 _("no username supplied"),
-                hint=_("use '@prog@ config --edit' " "to set your username"),
+                hint=_(
+                    'use `@prog@ config --user ui.username "First Last <me@example.com>"` to set your username'
+                ),
             )
         if "\n" in user:
             raise error.Abort(_("username %s contains a newline\n") % repr(user))

eden/scm/tests/test-commit-interactive.t

@@ -281,7 +281,7 @@ Modify end of plain file with username unset
   $ unset HGUSER
   $ hg commit -i --config ui.username= -d '8 0' -m end plain
   abort: no username supplied
-  (use 'hg config --edit' to set your username)
+  (use `hg config --user ui.username "First Last <me@example.com>"` to set your username)
   [255]
 
 

eden/scm/tests/test-committer.t

@@ -49,7 +49,7 @@
   $ echo "username = " >> .hg/hgrc
   $ hg commit -m commit-1
   abort: no username supplied
-  (use 'hg config --edit' to set your username)
+  (use `hg config --user ui.username "First Last <me@example.com>"` to set your username)
   [255]
 
 # test alternate config var