docs: hacking: remove note about rename detection
docs: hacking: remove note about rename detection

It has been enabled by default for over three years now:

commit 5d2a30d7d8777319c745804f040fa405d02169ce
Author:     Junio C Hamano <gitster@pobox.com>
CommitDate: 2016-04-03 10:29:22 -0700

    Merge branch 'mm/diff-renames-default'

https://github.com/git/git/commit/5d2a30d7d8777319c745804f040fa405d02169ce

Signed-off-by: Ján Tomko <4cab11cfb98d3c937327354a78eb07dbb6ee2bc6@redhat.com>
Reviewed-by: Daniel P. Berrangé <bb938cf255e055ff3507f2627d214e8e62118fcf@redhat.com>
Reviewed-by: Andrea Bolognani <3ada0bee826c753786fdbba72243dfba997094cf@redhat.com>

olafhering/libvirt,jfehlig/libvirt,fabianfreyer/libvirt,zippy2/libvirt,jfehlig/libvirt,fabianfreyer/libvirt,jardasgit/libvirt,crobinso/libvirt,zippy2/libvirt,fabianfreyer/libvirt,nertpinx/libvirt,jardasgit/libvirt,olafhering/libvirt,libvirt/libvirt,nertpinx/libvirt,crobinso/libvirt,nertpinx/libvirt,jardasgit/libvirt,libvirt/libvirt,jardasgit/libvirt,jfehlig/libvirt,olafhering/libvirt,fabianfreyer/libvirt,olafhering/libvirt,nertpinx/libvirt,jfehlig/libvirt,fabianfreyer/libvirt,libvirt/libvirt,crobinso/libvirt,jardasgit/libvirt,zippy2/libvirt,crobinso/libvirt,libvirt/libvirt,nertpinx/libvirt,zippy2/libvirt