refactor: remove unused function

Author: jp-knj

internal/const.go

@@ -4,8 +4,6 @@
 
 package astro
 
-import a "golang.org/x/net/html/atom"
-
 // Section 12.2.4.2 of the HTML5 specification says "The following elements
 // have varying levels of special parsing rules".
 // https://html.spec.whatwg.org/multipage/syntax.html#the-stack-of-open-elements
@@ -111,26 +109,3 @@ func isSpecialElement(element *Node) bool {
 	}
 	return false
 }
-
-var knownDirectiveMap = map[string]bool{
-	"client:load":    true,
-	"client:idle":    true,
-	"client:visible": true,
-	"client:only":    true,
-	"class:list":     true,
-	"set:text":       true,
-	"set:html":       true,
-}
-
-func IsKnownDirective(element *Node, attr *Attribute) bool {
-	if knownDirectiveMap[attr.Key] {
-		return true
-	}
-	if element.DataAtom == a.Script {
-		return attr.Key == "hoist"
-	}
-	if element.DataAtom == a.Style {
-		return attr.Key == "global"
-	}
-	return false
-}