Revert "sync: Recommend using --no-use-superproject if sync fails."

This reverts commit f907ced0fe.
Original change: https://gerrit-review.googlesource.com/c/git-repo/+/305622

Reason for revert: the hint was added when a superproject failure made
repo sync exit with an error. Since 8db30d6 the failure is non-fatal
and sync falls back to fetching normally, and these failures are often
transient (e.g. on 2026-09-23 a manifest change added
external/slackhq/compose-lints before the superproject had a commit
for it, until the change was reverted ~2h later). Following the hint
means users keep passing --no-use-superproject and bypass the
superproject even after the failure is gone.

The revert does not apply cleanly after the black reformat, so the
conflict was resolved by restoring the original message text.

Bug: 565845573
Change-Id: I5efadedd4d3d0002df50493fa29554ba9626fe82
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/634804
Commit-Queue: Ram Peri <ramperi@google.com>
Reviewed-by: Sam Saccone <samccone@google.com>
Tested-by: Ram Peri <ramperi@google.com>

subcmds/sync.py

@@ -923,12 +923,8 @@ later is required to fix a server side protocol bug.
             else:
                 if print_messages:
                     logger.warning(
-                        "%s: warning: Update of revisionId from superproject "
-                        "has failed, repo sync will not use superproject to "
-                        "fetch the source. Please resync with the "
-                        "--no-use-superproject option to avoid this repo "
-                        "warning.",
-                        m.path_prefix,
+                        "error: Update of revsionId from superproject "
+                        "has failed"
                     )
                 if update_result.fatal and opt.use_superproject is not None:
                     raise SuperprojectError()