[suggestion] An example for unifying the elements format

I hope to use same format for all elements to make things simpler. I hope/suggest that **the following format rules are valid for all julia element functions**. Special element functions may have other format rules.

1. The argument `[xxx]` will always be the `HTML content` no matter its position in `ele()`.
E.g. , Julia `ele("aa", "bb", [xxx], cc="dd")` => HTML `xxx`

2. There is only one argument `[xxx]` allowed in julia element function.
E.g., Julia `ele("aa", [xxx], [yyy],cc="dd")` **is NOT allowed !**.

3. If there is no argument `[xxx]`, the first string argument in julia element function will be the `HTML content`.
E.g., `ele("aa", bb="dd", "cc")` => HTML `aa`

4. argument `:xx` will be the `HTML attribute v-model="xx"`
E.g., `ele(:xx, bb="dd", "cc")` => HTML `cc`

5. argument `xx=:yy` will be the `HTML attribute :xx="yy"`
E.g., `ele(xx=:yy, bb="dd", "cc")` => HTML `cc`

6. other vue/custom attribute can be introduced by macro/string
E.g., julia ` btn("button",(@vclick "x=!x"),[])` => HTML ``
where, when click `button` the julia bool variable `x` will be changed to `!x`

The issue names no files, tests, or entry points. Start by locating the Julia element-function implementation and reviewing the existing discussion before attempting work. Done would require agreement on the proposed argument and attribute rules, followed by tests covering the accepted format.

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