comments: avoid using the gender of our users

We generally avoid specifying the gender of our users in order to be
more inclusive, but sometimes a few slip by due to habit.

Since by doing a little bit of rewording we can avoid this irrelevant
detail, let's do so.

Inspired-by: Derrick Stolee <dstolee@microsoft.com>
Helped-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/commit.c b/commit.c
index 42f8117..d888960 100644
--- a/commit.c
+++ b/commit.c
@@ -1164,7 +1164,7 @@ static void handle_signed_tag(struct commit *parent, struct commit_extra_header
 	/*
 	 * We could verify this signature and either omit the tag when
 	 * it does not validate, but the integrator may not have the
-	 * public key of the signer of the tag he is merging, while a
+	 * public key of the signer of the tag being merged, while a
 	 * later auditor may have it while auditing, so let's not run
 	 * verify-signed-buffer here for now...
 	 *