Debugger bar: change error panel delimiter

Replaces original delimiter pipe `|` with vertical tab character `\xB`, which is presumably not used as often.

Fixes broken render of error message containing pipe a character.

### Example:

Message: `Foo\Bar: Baz->[name|code|email] is not preloaded`
**Received** output:  `PHP Notice: Foo\Bar: Baz->[name in code:email] failed`
**Expected** output: `PHP Notice: Foo\Bar: Baz->[name|code|email] failed in .../foo/Bar.php:294`