Support “generate all implied end tags thoroughly”

When the parser encounters a `</template>` end tag and there are other
open elements, the HTML spec requires the parser to “generate all
implied end tags thoroughly”, which unlike “generate implied end tags”
also includes generating implied end tags for table-parts elements
(caption, colgroup, tbody, thead, tfoot, td, th, and tr).

Author: sideshowbarker

src/nu/validator/htmlparser/impl/TreeBuilder.java

@@ -3884,7 +3884,7 @@ private void endTagTemplateInHead() throws SAXException {
             errStrayEndTag("template");
             return;
         }
-        generateImpliedEndTags();
+        generateImpliedEndTagsThoroughly();
         if (errorHandler != null && !isCurrent("template")) {
             errUnclosedElements(eltPos, "template");
         }
@@ -4025,6 +4025,29 @@ private void generateImpliedEndTags() throws SAXException {
         }
     }
 
+    private void generateImpliedEndTagsThoroughly() throws SAXException {
+        for (;;) {
+            switch (stack[currentPtr].getGroup()) {
+                case CAPTION:
+                case COLGROUP:
+                case DD_OR_DT:
+                case LI:
+                case OPTGROUP:
+                case OPTION:
+                case P:
+                case RB_OR_RTC:
+                case RT_OR_RP:
+                case TBODY_OR_THEAD_OR_TFOOT:
+                case TD_OR_TH:
+                case TR:
+                    pop();
+                    continue;
+                default:
+                    return;
+            }
+        }
+    }
+
     private boolean isSecondOnStackBody() {
         return currentPtr >= 1 && stack[1].getGroup() == TreeBuilder.BODY;
     }