- Refactoring: Avoid unnecessary addEventListener false; change internal

jPicker function to class (used with `new`)
- Linting (ESLint): Add `valid-jsdoc` rule and make fixes; but turn off for
  now due to <https://github.com/eslint/eslint/issues/11036> and
  <https://github.com/eslint/eslint/issues/11037>
- Docs (JSDoc): Add some Markdown for variables, line breaks; tighten checks
  for overly generic types (though allow for `.Function` as in
  `jQuery.Function`) and avoid one previously missed instance

editor/extensions/ext-connector.js

@@ -148,7 +148,8 @@ export default {
 
     /**
     *
-    * @param {Element[]} [elem=selElems] Array of elements
+    * @param {Element[]} [elems=selElems] Array of elements
+    * @returns {undefined}
     */
     function findConnectors (elems = selElems) {
       const connectors = $(svgcontent).find(connSel);