errors: "strict subset" -> "ancestor"

The term "ancestor" is a bit more intuitive (and more consistent with
the documentation) than the term "strict subset".

Also, remove superfluous "ref", capitalize, and add some carriage
returns, changing:

    error: remote 'refs/heads/master' is not a strict subset of local ref 'refs/heads/master'. maybe you are not up-to-date and need to pull first?
    error: failed to push to 'ssh://linux-nfs.org/~bfields/exports/git.git'

to:

    error: remote 'refs/heads/master' is not an ancestor of
    local 'refs/heads/master'.
    Maybe you are not up-to-date and need to pull first?
    error: failed to push to 'ssh://linux-nfs.org/~bfields/exports/git.git'
Signed-off-by: NJ. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

builtin-branch.c

@@ -148,7 +148,7 @@ static int delete_branches(int argc, const char **argv, int force, int kinds)
 
 		if (!force &&
 		    !in_merge_bases(rev, &head_rev, 1)) {
-			error("The branch '%s' is not a strict subset of "
+			error("The branch '%s' is not an ancestor of "
 				"your current HEAD.\n"
 				"If you are sure you want to delete it, "
 				"run 'git branch -D %s'.", argv[i], argv[i]);

http-push.c

@@ -2241,7 +2241,11 @@ static int delete_remote_branch(char *pattern, int force)
 
 		/* Remote branch must be an ancestor of remote HEAD */
 		if (!verify_merge_base(head_sha1, remote_ref->old_sha1)) {
-			return error("The branch '%s' is not a strict subset of your current HEAD.\nIf you are sure you want to delete it, run:\n\t'git http-push -D %s %s'", remote_ref->name, remote->url, pattern);
+			return error("The branch '%s' is not an ancestor "
+				     "of your current HEAD.\n"
+				     "If you are sure you want to delete it,"
+				     " run:\n\t'git http-push -D %s %s'",
+				     remote_ref->name, remote->url, pattern);
 		}
 	}
 
@@ -2417,16 +2421,17 @@ int main(int argc, char **argv)
 			if (!has_sha1_file(ref->old_sha1) ||
 			    !ref_newer(ref->peer_ref->new_sha1,
 				       ref->old_sha1)) {
-				/* We do not have the remote ref, or
+				/*
+				 * We do not have the remote ref, or
 				 * we know that the remote ref is not
 				 * an ancestor of what we are trying to
 				 * push.  Either way this can be losing
 				 * commits at the remote end and likely
 				 * we were not up to date to begin with.
 				 */
-				error("remote '%s' is not a strict "
-				      "subset of local ref '%s'. "
-				      "maybe you are not up-to-date and "
+				error("remote '%s' is not an ancestor of\n"
+				      "local '%s'.\n"
+				      "Maybe you are not up-to-date and "
 				      "need to pull first?",
 				      ref->name,
 				      ref->peer_ref->name);

send-pack.c

@@ -297,9 +297,9 @@ static int send_pack(int in, int out, struct remote *remote, int nr_refspec, cha
 				 * commits at the remote end and likely
 				 * we were not up to date to begin with.
 				 */
-				error("remote '%s' is not a strict "
-				      "subset of local ref '%s'. "
-				      "maybe you are not up-to-date and "
+				error("remote '%s' is not an ancestor of\n"
+				      " local  '%s'.\n"
+				      " Maybe you are not up-to-date and "
 				      "need to pull first?",
 				      ref->name,
 				      ref->peer_ref->name);