branches: Escape percent signs in branch names

If a branch name contains a percent sign, it will be interpreted as a placeholder and color.py will fail to format it.

To avoid this, escape the percent signs prior to calling Coloring
method.

Bug: b/379090488
Change-Id: Id019c776bbf8cbed5c101f2773606f1d32c9e057
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/443801
Reviewed-by: Scott Lee <ddoman@google.com>
Tested-by: Josip Sokcevic <sokcevic@google.com>
Commit-Queue: Josip Sokcevic <sokcevic@google.com>

subcmds/branches.py

diff --git a/subcmds/branches.py b/subcmds/branches.py
index 08c6389..b7a45b4 100644
--- a/subcmds/branches.py
+++ b/subcmds/branches.py
@@ -167,7 +167,10 @@
             else:
                 published = " "
 
-            hdr("%c%c %-*s" % (current, published, width, name))
+            # A branch name can contain a percent sign, so we need to escape it.
+            # Escape after f-string formatting to properly account for leading
+            # spaces.
+            hdr(f"{current}{published} {name:{width}}".replace("%", "%%"))
             out.write(" |")
 
             _RelPath = lambda p: p.RelPath(local=opt.this_manifest_only)