Auto-parenthesize multipart strings

[JelleZijlstra]

With Black's new ability to split overly long strings, it would be nice if it would also put parentheses automatically in at least some places.

In this diff:

     fix_fstab_commands = [
-        "grep -q /dev/xvdd /etc/fstab || sed -i '2i/dev/xvdd /mnt auto defaults,nofail 0 2' /etc/fstab",
-        "grep -q /dev/nvme1n1 /etc/fstab || sed -i '2i/dev/nvme1n1 /mnt auto defaults,nofail 0 2' /etc/fstab",
+        "grep -q /dev/xvdd /etc/fstab || sed -i '2i/dev/xvdd /mnt auto defaults,nofail"
+        " 0 2' /etc/fstab",
+        "grep -q /dev/nvme1n1 /etc/fstab || sed -i '2i/dev/nvme1n1 /mnt auto"
+        " defaults,nofail 0 2' /etc/fstab",
     ]

It's hard to see in the output where each of the two commands start (you have to look for a tiny comma in the middle). It would look better if there were parens around the two commands, so they are clearly visually separated.

We already know to do this in other contexts:

-        help="Import functions for performance analysis. Can't be used with other startup script options.",
+        help=(
+            "Import functions for performance analysis. Can't be used with other"
+            " startup script options."
+        ),