''' is not defined in HTML 4, and some browsers (for instance IE at least through 8) do not support it.
It is however part of XML 1 (and thus XHTML 1), and is also defined in HTML 5 provisional, so it's fine to accept it.
Normalization seems to already handle turning the ' named char reference into ' so we don't have any compatibility worries.
Also added a comment on the def in Sanitizer that it shouldn't be used in output.
'amp' => 38,
'and' => 8743,
'ang' => 8736,
- 'apos' => 39,
+ 'apos' => 39, // New in XHTML & HTML 5; avoid in output for compatibility with IE.
'Aring' => 197,
'aring' => 229,
'asymp' => 8776,
!! end
+!! test
+Confirm that 'apos' named character reference doesn't make it to output (not legal in HTML 4)
+!! input
+Text's been normalized?
+!! result
+<p>Text's been normalized?
+</p>
+!! end
+
+
TODO:
more images
more tables