Sometimes you wish to type:

// The following is really awesome:

$a = $a + 1;

However the code checker reports "Inline comments must end in full-stops, exclamation marks, or question marks".

Therefore it is desirable for colons (':') to be accepted.

Edited by Eloy to clarify it's about to allow colons before code (i.e. at the end of the comment). They are valid everywhere else within the comment already.