Fix bug in isHtmlTag()

Fix what seems to be a typo. j should iterate through all tagname, so it
should be initialized to zero. The test exposes this bug.

html.go

@@ -663,7 +663,7 @@ func isHtmlTag(tag []byte, tagname string) bool {
 		i++
 	}
 
-	j := i
+	j := 0
 	for ; i < len(tag); i, j = i+1, j+1 {
 		if j >= len(tagname) {
 			break

inline_test.go

@@ -63,6 +63,14 @@ func doTestsInlineParam(t *testing.T, tests []string, extensions, htmlFlags int)
 	}
 }
 
+func TestRawHtmlTag(t *testing.T) {
+	tests := []string{
+		"zz <style>p {}</style>\n",
+		"<p>zz p {}</p>\n",
+	}
+	doTestsInlineParam(t, tests, 0, HTML_SKIP_STYLE)
+}
+
 func TestEmphasis(t *testing.T) {
 	var tests = []string{
 		"nothing inline\n",