MediaWiki:Gadget-ForceEditLinks.js

function forceLinksToEdit() {
    var links = document.getElementById('bodyContent').getElementsByTagName('a');
    for(var i=0; i<links.length; i++) {
        if(!links[i].href.match('/w/index.php')) {
            links[i].href = links[i].href.replace(/(#|$)/, "?action=edit$1");
        }
    }
}

$(forceLinksToEdit);