Markdown: add Table, Emoji and Highlight Text

- Emoji: `😂`, `👍`
- Highlight Text: `==very important==`
- Table:
```md
| abc | abc |
| --- | --- |
| abc | abc |
```

FEATURE: 455561

Which was not added from the extended syntax:

- Heading IDs: `### My Great Heading {#custom-id}`
- Subscript: `H~2~O`
- Superscript: `X^2^`
- Definition Lists:
```
First Term
: This is the definition of the first term.
```

The rest was already done