Fix hash render end with colon (#31319) (#31346)

Backport #31319 by @lunny

Fix a hash render problem like `<hash>: xxxxx` which is usually used in
release notes.

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

modules/markup/html_internal_test.go

@@ -380,6 +380,7 @@ func TestRegExp_sha1CurrentPattern(t *testing.T) {
 		"(abcdefabcdefabcdefabcdefabcdefabcdefabcd)",
 		"[abcdefabcdefabcdefabcdefabcdefabcdefabcd]",
 		"abcdefabcdefabcdefabcdefabcdefabcdefabcd.",
+		"abcdefabcdefabcdefabcdefabcdefabcdefabcd:",
 	}
 	falseTestCases := []string{
 		"test",