Remove inaccurate statement about the insertion mode and CDATA sections

[sirreal]

The explanation of the insertion mode includes this inaccurate line (bold mine):

The insertion mode affects how tokens are processed and whether CDATA sections are supported.

CDATA section handling depends on the adjusted current node, not the insertion mode:

"[CDATA["
Consume those characters. If there is an adjusted current node and it is not an element in the HTML namespace, then switch to the CDATA section state. Otherwise, this is a cdata-in-html-content parse error. Create a comment token whose data is "[CDATA[". Switch to the bogus comment state.

If CDATA sections are not handled as bogus comments, they emit character tokens.

See #4016 (comment).

---

/parsing.html ( diff )

[sirreal]

From #4015:

https://html.spec.whatwg.org/multipage/parsing.html#parsing-main-inforeign is not mentioned, although it is where CDATA sections are supported. If in foreign content is not an insertion mode, then the insertion mode doesn't affect whether CDATA sections are supported...