Offer completion and syntax highlighting for inlined CSS & HTML in JS/TS/JSX/TSX

The wwd uses a generic editor to open html, css, js, jsx, ts, tsx, etc.

Would be nice to support all these languages (code completion and syntax highlighting) within this generic editor. It should not matter, which language is within which filetype. For example, if wwd detects css or html within js/jsx/ts/tsx files, then it should provide code completion and syntax highlighting. As css and html can be added within js/jsx/ts/tsx files (for example, by template literals), the generic editor should be a hybrid editor.

Please improve at least these cases:

• There is actually no content assist and code highlighting of html and css placed within a template literal in a .js-file. Please provide support.

• There is actually content assist and syntax highlighting of html in jsx, but typing, for example, a <div>- tag does not automatically produce its closing tag. So I have to add it manually.

• Using html and css within template literal should provide content assist and code completion within this generic editor for ALL file types.

For example:

// defined within js file (html and css within template literal -> no code completion/no syntax highlighting)
const component = {
            label: `<span style="color: red">hello</span>`,
            input:`<input name="hi" type="checkbox" ${conf.enabled ? 'checked' : ''} ${!conf.disabled ? 'disabled' : ''}>`,
            isCheckbox: true
    }

There were efforts in the past in this direction https://github.com/eclipse/wildwebdeveloper/issues/151. But the css, html support (=code completion and syntax highlighting) in template literal and within js, jsx, ts, tsx is not sufficient.

首先查看此处描述的通用编辑器行为，以及 issue 151 中之前的工作。复现列出的 JavaScript、JSX、TypeScript、TSX、模板字面量、HTML 和 CSS 场景；当内容辅助、语法高亮和 HTML 标签自动闭合在所请求的文件类型中正常工作时，即表示完成。