Second default keys, also in menu lines

F2 Deselect All, Cmd+Shift+T Effect Controls, Cmd+Alt+Left / Right Go to Start /
End, Cmd+Shift+/ Add to Render Queue.

Effect Controls is a menu entry with bound parameters, which could hold one key:
a menu line can now give further default keys after a comma
(F3, Cmd+Shift+T); the menus show the first. MenuEntry gains alt_shortcuts.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

crates/engine/src/commands/render_queue.rs

@@ -998,7 +998,7 @@ pub fn specs() -> Vec<CommandSpec> {
             "renderQueue.add",
             "Add to Render Queue",
             ["Composition"],
-            Some("Cmd+M"),
+            ["Cmd+M", "Cmd+Shift+/"],
             "{comp?: id|name, template?: Render Settings template, format?: h264|hevc|av1|prores|uncompressed|webm|png|jpeg|tiff|exr|gif|wav|aiff, output?: path|template, log?: errorsOnly|plusSettings|plusPerFrameInfo, quality?: best|draft|1-100 (jpeg, webm), resolution?: full|half|third|quarter|scale, proxyUse?, effects?, solo?, guideLayers?, colorDepth?, frameBlending?, fieldRender?, pulldown?, motionBlur?, timeSpan?: workArea|comp|custom, start?: s, end?: s, duration?: s, frameRate?: fps|null, skipExisting?: bool, storageOverflow?: bool, channels?: rgb|rgba|alpha, color?, bitrate?: kbps, webmBitrate?, keyframeInterval?, proresProfile?, profile?, level?, rateControl?, webmCodec?, audioBitrate?, opusApplication?, crop?, resize?, includeProjectLink?, audio?: auto|on|off, sampleRate?, audioChannels?, audioFormat?, loop?: bool (values as in setRenderSettings / setOutputModule)}",
             can_add,
             add