[FL-3925, FL-3942, FL-3944] JS features & bugfixes (SDK 0.2) (#4075)

* feat: JS GPIO PWM, JS GUI Widget view; fix: JS EvtLoop stop on request, JS EvtLoop stop on error
* fix: f18 build
* docs: widget
* fix: js unit test
* change feature naming

Co-authored-by: あく <alleteam@gmail.com>

documentation/js/js_gui.md

@@ -27,23 +27,23 @@ always access the canvas through a viewport.
 In Flipper's terminology, a "View" is a fullscreen design element that assumes
 control over the entire viewport and all input events. Different types of views
 are available (not all of which are unfortunately currently implemented in JS):
-| View                 | Has JS adapter?  |
-|----------------------|------------------|
-| `button_menu`        | ❌               |
-| `button_panel`       | ❌               |
-| `byte_input`         | ❌               |
-| `dialog_ex`          | ✅ (as `dialog`) |
-| `empty_screen`       | ✅               |
-| `file_browser`       | ❌               |
-| `loading`            | ✅               |
-| `menu`               | ❌               |
-| `number_input`       | ❌               |
-| `popup`              | ❌               |
-| `submenu`            | ✅               |
-| `text_box`           | ✅               |
-| `text_input`         | ✅               |
-| `variable_item_list` | ❌               |
-| `widget`             | ❌               |
+| View                 | Has JS adapter?       |
+|----------------------|-----------------------|
+| `button_menu`        | ❌                    |
+| `button_panel`       | ❌                    |
+| `byte_input`         | ✅                    |
+| `dialog_ex`          | ✅ (as `dialog`)      |
+| `empty_screen`       | ✅                    |
+| `file_browser`       | ✅ (as `file_picker`) |
+| `loading`            | ✅                    |
+| `menu`               | ❌                    |
+| `number_input`       | ❌                    |
+| `popup`              | ❌                    |
+| `submenu`            | ✅                    |
+| `text_box`           | ✅                    |
+| `text_input`         | ✅                    |
+| `variable_item_list` | ❌                    |
+| `widget`             | ✅                    |
 
 In JS, each view has its own set of properties (or just "props"). The programmer
 can manipulate these properties in two ways:

documentation/js/js_gui__widget.md

@@ -0,0 +1,25 @@
+# js_gui__widget {#js_gui__widget}
+
+# Widget GUI view
+Displays a combination of custom elements on one screen
+
+<img src="widget.png" width="200" alt="Sample screenshot of the view" />
+
+```js
+let eventLoop = require("event_loop");
+let gui = require("gui");
+let widgetView = require("gui/widget");
+```
+
+This module depends on the `gui` module, which in turn depends on the
+`event_loop` module, so they _must_ be imported in this order. It is also
+recommended to conceptualize these modules first before using this one.
+
+# Example
+For an example refer to the `gui.js` example script.
+
+# View props
+This view does not have any props.
+
+# Children
+This view has the elements as its children.