JSX blocks miss components with numbers

[johno]

Subject of the issue

When a JSX block is opened up with a component that has a number in it, we fail to recognize it as a jSX block properly.

# Hello, world!

<Alt2 />

This is likely due to BLOCKS_REGEX not accounting for numbers, which is used to determine JSX blocks.

Expected behaviour

Alt2 should be rendered as JSX.

Actual behaviour

It's parsed as a paragraph.

[johno]

No longer the case, was fixed a while back and I forgot to close this.