- Enhancement (svgIcons): Fix JSDoc param def; add alt options

- Accessibility: Begin work, add aria-label to some buttons and
    form controls; add `role=main`; `<img alt>`; `<iframe title>`
- i18n: Add `lang` attribute
- Refactoring: lbs, simplify i18nized element retrieval call
- Docs: Some JSDoc descriptions, JSDoc spacing, fix svgIcons param
    def; add todo
- Testing: Avoid reporting meta-viewport (have own zooming
    controls and difficult to fix)

dist/extensions/ext-server_moinsave.js

@@ -4887,7 +4887,7 @@ var svgEditorExtension_server_moinsave = (function () {
 
                 /* const target = */
 
-                $('<iframe name="output_frame" style="width: 0; height: 0;" src="#"/>').appendTo('body');
+                $("<iframe name=\"output_frame\" title=\"".concat(strings.hiddenframe, "\"\n        style=\"width: 0; height: 0;\" src=\"#\"/>")).appendTo('body');
                 svgEditor.setCustomHandlers({
                   save: function () {
                     var _save = _asyncToGenerator(