exp/html/atom: add some more atoms.

R=r, dsymonds
CC=golang-dev
https://golang.org/cl/6298085

src/pkg/exp/html/atom/gen.go

@@ -599,6 +599,7 @@ var extra = []string{
 	"basefont",
 	"bgsound",
 	"big",
+	"blink",
 	"center",
 	"color",
 	"desc",
@@ -624,8 +625,12 @@ var extra = []string{
 	"noembed",
 	"noframes",
 	"plaintext",
+	"prompt",
+	"public",
+	"spacer",
 	"strike",
 	"svg",
+	"system",
 	"tt",
 	"xmp",
 }

src/pkg/exp/html/atom/table_test.go

@@ -30,6 +30,7 @@ var testAtomList = []string{
 	"bdo",
 	"bgsound",
 	"big",
+	"blink",
 	"blockquote",
 	"body",
 	"border",
@@ -263,6 +264,8 @@ var testAtomList = []string{
 	"pre",
 	"preload",
 	"progress",
+	"prompt",
+	"public",
 	"q",
 	"radiogroup",
 	"readonly",
@@ -289,6 +292,7 @@ var testAtomList = []string{
 	"sizes",
 	"small",
 	"source",
+	"spacer",
 	"span",
 	"span",
 	"spellcheck",
@@ -305,6 +309,7 @@ var testAtomList = []string{
 	"summary",
 	"sup",
 	"svg",
+	"system",
 	"tabindex",
 	"table",
 	"target",