move extensions to own package

packages/tiptap-extensions/src/marks/Italic.js

@@ -0,0 +1,31 @@
+import { Mark } from 'tiptap'
+import { toggleMark } from 'tiptap-commands'
+
+export default class ItalicMark extends Mark {
+
+	get name() {
+		return 'italic'
+	}
+
+	get schema() {
+		return {
+			parseDOM: [
+				{ tag: 'i' },
+				{ tag: 'em' },
+				{ style: 'font-style=italic' },
+			],
+			toDOM: () => ['em', 0],
+		}
+	}
+
+	keys({ type }) {
+		return {
+			'Mod-i': toggleMark(type),
+		}
+	}
+
+	command({ type }) {
+		return toggleMark(type)
+	}
+
+}