Refactor markup render system (#32533)

Remove unmaintainable sanitizer rules. No need to add special "class"
regexp rules anymore, use RenderInternal.SafeAttr instead, more details
(and examples) are in the tests

modules/markup/markdown/ast.go

@@ -34,13 +34,6 @@ func NewDetails() *Details {
 	}
 }
 
-// IsDetails returns true if the given node implements the Details interface,
-// otherwise false.
-func IsDetails(node ast.Node) bool {
-	_, ok := node.(*Details)
-	return ok
-}
-
 // Summary is a block that contains the summary of details block
 type Summary struct {
 	ast.BaseBlock
@@ -66,13 +59,6 @@ func NewSummary() *Summary {
 	}
 }
 
-// IsSummary returns true if the given node implements the Summary interface,
-// otherwise false.
-func IsSummary(node ast.Node) bool {
-	_, ok := node.(*Summary)
-	return ok
-}
-
 // TaskCheckBoxListItem is a block that represents a list item of a markdown block with a checkbox
 type TaskCheckBoxListItem struct {
 	*ast.ListItem
@@ -103,14 +89,7 @@ func NewTaskCheckBoxListItem(listItem *ast.ListItem) *TaskCheckBoxListItem {
 	}
 }
 
-// IsTaskCheckBoxListItem returns true if the given node implements the TaskCheckBoxListItem interface,
-// otherwise false.
-func IsTaskCheckBoxListItem(node ast.Node) bool {
-	_, ok := node.(*TaskCheckBoxListItem)
-	return ok
-}
-
-// Icon is an inline for a fomantic icon
+// Icon is an inline for a Fomantic UI icon
 type Icon struct {
 	ast.BaseInline
 	Name []byte
@@ -139,13 +118,6 @@ func NewIcon(name string) *Icon {
 	}
 }
 
-// IsIcon returns true if the given node implements the Icon interface,
-// otherwise false.
-func IsIcon(node ast.Node) bool {
-	_, ok := node.(*Icon)
-	return ok
-}
-
 // ColorPreview is an inline for a color preview
 type ColorPreview struct {
 	ast.BaseInline