feat(istanbul-reports): Enable keyboard shortcuts on HTML report file…

… listing view (#265)

* Keyboard shortcuts for low coverage in file listing view

* Fix linting issues

packages/istanbul-reports/lib/html/assets/block-navigation.js

@@ -1,13 +1,19 @@
 var jumpToCode = (function init() {
-    // Classes of code we would like to highlight
+    // Classes of code we would like to highlight in the file view
     var missingCoverageClasses = ['.cbranch-no', '.cstat-no', '.fstat-no'];
 
+    // Elements to highlight in the file listing view
+    var fileListingElements = ['td.pct.low'];
+
     // We don't want to select elements that are direct descendants of another match
     var notSelector = ':not(' + missingCoverageClasses.join('):not(') + ') > '; // becomes `:not(a):not(b) > `
 
     // Selecter that finds elements on the page to which we can jump
     var selector =
-        notSelector + missingCoverageClasses.join(', ' + notSelector); // becomes `:not(a):not(b) > a, :not(a):not(b) > b`
+        fileListingElements.join(', ') +
+        ', ' +
+        notSelector +
+        missingCoverageClasses.join(', ' + notSelector); // becomes `:not(a):not(b) > a, :not(a):not(b) > b`
 
     // The NodeList of matching elements
     var missingCoverageElements = document.querySelectorAll(selector);