U+2005 etc. is (sometimes) stripped from html

Prettier 1.19.1 Playground link

# Options (if any):
--single-quote

Input:

<p><span>X</span>   or   <span>Y</span></p>
<p>X   or   Y</p>

Output:

<p><span>X</span> or <span>Y</span></p>
<p>X   or   Y</p>

Expected behavior:

U+2005 should not be turned into a regular space.

From a quick test, this also happens for similar characters in the Unicode General Punctuation block.

[fisker]

I think I fixed it

$ node -p "require('prettier').format('<i /> \u2005 | \u2005 <i />', {parser:'html'}) === '<i /> \u2005 | \u2005 <i />\n'"
false

$ node -p "require('.').format('<i /> \u2005 | \u2005 <i />', {parser:'html'}) === '<i /> \u2005 | \u2005 <i />\n'"
true

minimal reproduction

"<i /> \u2005 | \u2005 <i />"

[fisker]

Found the problem, thank you.

$ node -p "require('prettier').format('<i>X</i>\u0020\u2005\u0020<i>X</i>', {parser:'html'}) === '<i>X</i>\u0020\u2005\u0020<i>X</i>\n'"
false