[Ldap] Update ldap.rst

[jljohnstone]

Add single quotes in filter option documentation

[javiereguiluz]

Jason, thanks for this contribution!

Looking at https://github.com/symfony/symfony/blob/b617ee0cd014767fcf52971a9644d2f0bfbdf719/src/Symfony/Component/Ldap/Adapter/AbstractQuery.php#L43-L45 it seems that both strings and arrays are accepted. But I don't know LDAP much, so I'm not sure if 'foo, bar' is equivalent to ['foo', 'bar'] (maybe the first one means AND and the second one means OR?)

Let's ask to someone who knows LDAP well. Thanks!

[OskarStark]

@jljohnstone can you confirm that the code before works as well? Or did you just spot this "issue" while reading the docs?

[jljohnstone]

@OskarStark No, the documented code did not work for me. I had to use separate array elements to get filtering to work.

[wouterj]

I just tested this in a Symfony functional test and I can confirm that this indeed needs to be an array.

[javiereguiluz]

Jason, thanks a lot for fixing this ... and congrats on your first Symfony Docs contribution 🎉