refactor(tiptap-extensions): Do not import the full lowlight library.

BREAKING CHANGE: `CodeBlockHighlight` was importing the full `lowlight` libraries, including _all_
syntax highlightning definitions from `highlight.js`. The new behavior changes the signature of
`CodeBlockHighlight` to accept an object with all syntax highlightning definitions. This means that
now the user of the library __MUST__ import languages themselves and tiptap will no longer
bundle the full `highlight.js` in itself.

examples/Components/Routes/CodeHighlighting/examples.js

@@ -26,3 +26,25 @@ body, .usertext {
     content: attr(href)
   }
 }`
+
+
+export const explicitImportExample = `import javascript from 'highlight.js/lib/languages/javascript'
+import { Editor } from 'tiptap'
+
+export default {
+  components: {
+    Editor
+  },
+  data() {
+    return {
+      extensions: [
+        new CodeBlockHighlightNode({
+          languages: {
+            javascript,
+            css
+          }
+        })
+      ]
+    }
+  }
+}`;