tests: stabilize test-git-interop.t for some versions of git stable

tests: stabilize test-git-interop.t for some versions of git

Not sure why this differs on my system, but it's likely due to running 2.17.1 on
Ubuntu 18.04.

Differential Revision: https://phab.mercurial-scm.org/D10520

--- a/tests/test-git-interop.t	Fri Apr 30 02:25:10 2021 +0200
+++ b/tests/test-git-interop.t	Tue Apr 27 00:23:05 2021 -0400
@@ -67,6 +67,7 @@
   On branch master
   Untracked files:
     (use "git add <file>..." to include in what will be committed)
+   (?)
   	gamma
   
   nothing added to commit but untracked files present (use "git add" to track)
@@ -134,6 +135,7 @@
   On branch master
   Untracked files:
     (use "git add <file>..." to include in what will be committed)
+   (?)
   	gamma
   
   nothing added to commit but untracked files present (use "git add" to track)
@@ -153,7 +155,9 @@
   $ git status
   On branch master
   Changes to be committed:
-    (use "git restore --staged <file>..." to unstage)
+    (use "git restore --staged <file>..." to unstage) (?)
+    (use "git reset HEAD <file>..." to unstage) (?)
+   (?)
   	new file:   gamma
   
 
@@ -165,6 +169,7 @@
   On branch master
   Untracked files:
     (use "git add <file>..." to include in what will be committed)
+   (?)
   	gamma
   
   nothing added to commit but untracked files present (use "git add" to track)