Make our hail-mary logic a little more flexible.

(Jason's original implementation just truncated the $sn, no matter
what. I modified it slightly.)

Signed-off-by: Jesse Vincent <jesse@keyboard.io>

bin/find-device-port-macos

@@ -77,6 +77,8 @@ sub try_for_location_id {
 
 sub try_for_sn_prefix {
     my $sn = shift;
+    # If macOS has appended 'E', take it off to maximise our chances of a match.
+    $sn =~ s/E$//;
 
     # If none of the above tests succeeds, just list the directory and see if there are any
     # files that have the device shortname that we expect: