removes showSource feature-flag remnants (#2766)
removes showSource feature-flag remnants (#2766)

* removes showSource feature-flag remnants

* response to PR feedback

borian/debugger.html,bomsy/debugger.html,jbhoosreddy/debugger.html,jasonLaster/debugger.html,bomsy/debugger.html,wldcordeiro/debugger.html,borian/debugger.html,bomsy/debugger.html,jbhoosreddy/debugger.html,amitzur/debugger.html,darkwing/debugger.html,tommai78101/debugger.html,darkwing/debugger.html,ruturajv/debugger.html,amitzur/debugger.html,bomsy/debugger.html,darkwing/debugger.html,jbhoosreddy/debugger.html,amitzur/debugger.html,jasonLaster/debugger.html,clarkbw/debugger.html,clarkbw/debugger.html,ruturajv/debugger.html,devtools-html/debugger.html,devtools-html/debugger.html,devtools-html/debugger.html,wldcordeiro/debugger.html,darkwing/debugger.html,borian/debugger.html,jbhoosreddy/debugger.html,bomsy/debugger.html,devtools-html/debugger.html,wldcordeiro/debugger.html,clarkbw/debugger.html,jasonLaster/debugger.html,jasonLaster/debugger.html,darkwing/debugger.html,tommai78101/debugger.html,ruturajv/debugger.html,ruturajv/debugger.html,wldcordeiro/debugger.html,wldcordeiro/debugger.html,amitzur/debugger.html,jbhoosreddy/debugger.html,devtools-html/debugger.html,jasonLaster/debugger.html,borian/debugger.html,amitzur/debugger.html,tommai78101/debugger.html,wldcordeiro/debugger.html,jasonLaster/debugger.html,ruturajv/debugger.html,clarkbw/debugger.html,devtools-html/debugger.html,clarkbw/debugger.html,ruturajv/debugger.html,bomsy/debugger.html,amitzur/debugger.html,borian/debugger.html,ruturajv/debugger.html,jasonLaster/debugger.html,tommai78101/debugger.html,borian/debugger.html,darkwing/debugger.html,tommai78101/debugger.html,jbhoosreddy/debugger.html,jbhoosreddy/debugger.html,devtools-html/debugger.html,bomsy/debugger.html,wldcordeiro/debugger.html,darkwing/debugger.html