Fix `FormHelper::postLink()` description.
Fix `FormHelper::postLink()` description.

Update description with a short explanation that considers the
`block` option.

mvdriel/cakephp,ionas/cakephp,jeffblack360/cakephp,berrygoudswaard/cakephp,ndm2/cakephp,CVO-Technologies/cakephp,justinyost/cakephp,davidyell/cakephp,ionas/cakephp,cakephp-fr/cakephp,garethellis36/cakephp,cakephp-fr/cakephp,dakota/cakephp,Phillaf/cakephp,ndm2/cakephp,michaelze/cakephp,tgr0ss/cakephp,tenkoma/cakephp,CVO-Technologies/cakephp,mvdriel/cakephp,ADmad/cakephp,gmponos/cakephp,thinkingmedia/cakephp,timhoeppner/cakephp,ndm2/cakephp,petteyg/cakephp,gmponos/cakephp,elboletaire/cakephp,nrother/cakephp,cakephp/cakephp,HavokInspiration/cakephp,ndm2/cakephp,thinkingmedia/cakephp,elboletaire/cakephp,michaelze/cakephp,gmponos/cakephp,dakota/cakephp,mvdriel/cakephp,CVO-Technologies/cakephp,garethellis36/cakephp,garethellis36/cakephp,tenkoma/cakephp,michaelze/cakephp,petteyg/cakephp,timhoeppner/cakephp,ionas/cakephp,cakephp-fr/cakephp,bravo-kernel/cakephp,cakephp/cakephp,CakeDC/cakephp,Phillaf/cakephp,petteyg/cakephp,CakeDC/cakephp,dakota/cakephp,cakephp/cakephp,HavokInspiration/cakephp,petteyg/cakephp,CakeDC/cakephp,HavokInspiration/cakephp,cakephp/cakephp,ADmad/cakephp,berrygoudswaard/cakephp,jeffblack360/cakephp,tenkoma/cakephp,justinyost/cakephp,justinyost/cakephp,Phillaf/cakephp,tgr0ss/cakephp,ADmad/cakephp,nrother/cakephp,CakeDC/cakephp,berrygoudswaard/cakephp,jeffblack360/cakephp,tenkoma/cakephp,davidyell/cakephp,bravo-kernel/cakephp,thinkingmedia/cakephp,garethellis36/cakephp,nrother/cakephp,elboletaire/cakephp,dakota/cakephp,ADmad/cakephp,timhoeppner/cakephp,mvdriel/cakephp,bravo-kernel/cakephp,davidyell/cakephp,tgr0ss/cakephp