Drop 'to' option for link rules from manpage

The apparmor.d manpage listed 'to' as an alternative for '->' in link rules.

However, the parser doesn't accept 'to', none of our examples and tests include it, and nobody ever complained about it. Therefore I'll call this a documentation bug ;-) and simply adjust the manpage to only list '->' as valid syntax.

I propose this patch for 2.11..master

approved this merge request

merged

mentioned in commit 041cd95a

mentioned in commit 21c3d57f

mentioned in commit fdb9a6e4

mentioned in commit 832a0c2d