fix: restore html report selection highlighting

CHANGES.rst

@@ -34,6 +34,10 @@ Unreleased
   - Coverage will no longer generate "Already imported a file that will be
     measured" warnings about coverage itself (`issue 905`_).
 
+- The HTML report uses j/k to move up and down among the highlighted chunks of
+  code.  They used to highlight the current chunk, but 5.0 broke that behavior.
+  Now the highlighting is working again.
+
 - The JSON report now includes ``percent_covered_display``, a string with the
   total percentage, rounded to the same number of decimal places as the other
   reports' totals.

coverage/htmlfiles/coverage_html.js

@@ -311,11 +311,6 @@ coverage.line_elt = function (n) {
     return $("#t" + n);
 };
 
-// Return the nth line number div.
-coverage.num_elt = function (n) {
-    return $("#n" + n);
-};
-
 // Set the selection.  b and e are line numbers.
 coverage.set_sel = function (b, e) {
     // The first line selected.
@@ -514,9 +509,9 @@ coverage.show_selection = function () {
     var c = coverage;
 
     // Highlight the lines in the chunk
-    $(".linenos .highlight").removeClass("highlight");
+    $("#source .highlight").removeClass("highlight");
     for (var probe = c.sel_begin; probe > 0 && probe < c.sel_end; probe++) {
-        c.num_elt(probe).addClass("highlight");
+        c.line_elt(probe).addClass("highlight");
     }
 
     c.scroll_to_selection();