There are plenty of legitimate scripts in the tree that begin with a
`#!`, but also a few that seem to be marked executable by mistake.
Found them with this command -- it gets executable files known to Git,
filters to the ones that don't start with a `#!`, and then unmarks
them as executable:
$ git ls-files --stage \
| perl -lane 'print $F[3] if (!/^100644/)' \
| while read f; do
head -c2 "$f" | grep -qxF '#!' \
|| chmod a-x "$f"; \
done
Looking at the list by hand confirms that we didn't sweep up any
files that should have the executable bit after all. In particular
* The `.psd` files are images from Photoshop.
* The `.bat` files sure look like things that can be run.
But we have lots of other `.bat` files, and they don't have
this bit set, so it must not be needed for them.
Automerge-Triggered-By: @benjaminp
