When <cxx-note> is a child of <cxx-function>, the block should not be surrounded by [ -- end note]

[jaredhoberock]

An example of where this problem occurs is at 2.2.1.17 of the Library Fundamentals TS.

[jyasskin]

The standard has [Note: ... --end note] blocks inside function definitions; for example [syserr.errcat.nonvirtuals] in operator<. If you want it to look like

Notes: text

instead, use a <cxx-notes> tag.

@zygoloid should we prefer "Notes" blocks over [Note:...--end note] blocks in functions?