Pretty print lowercase jsx as attr of a jsx with braces.

[IwanKaramazow]

Prints braces around jsx attributes containing lowercase jsx:

<form label=<div /> />;
/* post-refmt: */
<form label={<div />} />;

Makes lowercase jsx as jsx attribute consistent with #1745

[chenglou]

Doing jsxAttrs = [] is O(1) instead of O(n). Or just match on a 3-tuple

[IwanKaramazow]

Thanks! Should have thought about this...

[chenglou]

Thanks! So what caused the small regression before?

[IwanKaramazow]

I wrongly assumed that 'createElement' was part of lowercase jsx

[chenglou]

Oh so you thought it was div.createElement? kk.

Thanks!