Description:
------------
http://www.php.net/manual/en/language.types.string.php#language.types.st
ring.syntax.single says:

"To specify a literal backslash before a single quote, or at the end of 
the string, double it (\\)."

This is incomplete, It should be added "before another backslash". Like 
this:

"To specify a literal backslash before a single quote, before another 
backslash, or at the end of the string, double it (\\)."






Reproduce code:
---------------
To echo a literal single-quoted string containing only two backslash characters, I start by writing the enclosing quotes and the two backslashes themselves:

echo '\\';

Then I should escape the second backslash, because it is "at the end of the string". It gives

echo '\\\';

The first backslash, according the documentation, should not escaped, because it is neither before a single quote or at the end of the string.

Expected result:
----------------
Two backslashes are echoed.

Actual result:
--------------
Parse error.