Add webkit_ref to platform status entries

[takenspc]

This PR added webkit_ref to following entries to reflect WebKit's implementation status.

• asmjs: removed webkit_ref (WebKit Feature Status has removed the corresponding entry)
• async-clipboard: Async Clipboard API
• async-function: async/await
• block-autoplay: added webkit_status (WebKit Feature Status has no corresponding entries)
• canvas-media-capture: added webkit_status (WebKit has supported HTMLCanvasElement.captureStream())
• css-backdrop-filter: Filter Effects backdrop-filter property
• css-clip-path: added webkit_status (WebKit has supported clip-path))
• css-logical-properties: CSS Logical Properties and Values Level 1
• css-scroll-snap: CSS Scroll Snap Points Module Level 1
• dialog-element: Dialog Element
• fetch: Fetch
• gamepad: Gamepad
• html-templates: Template Element
• htmlcanvaselement-toblob: added webkit_status (WebKit has supported HTMLCanvasElement.toBlob())
• javascript-modules: Modules
• media-recorder: MediaStream Recording API
• microtask-api: added webkit_status (WebKit has supported HTMLCanvasElement.toBlob())
• performance-server-timing: removed webkit_ref (WebKit Feature Status has no corresponding entries)
• pointer-events: Pointer Events Level 2
• pointerlock: Pointer Lock
• subresource-integrity: Subresource Integrity
• text-decoration-4: CSS Text Decoration Level 4
• visual-viewport-api: Visual Viewport API
• webaudio: Web Audio
• webvr: removed webkit_ref (WebKit Feature Status has removed the corresponding entry)