Encoding::__toString complies with PHP specification from now on

[k00ni]

Besides an if-else I also added more details in code and text.

Hint came from @igor-krein in #85 (comment):

Currently, in the Encoding.php, there is a "magic" function __toString() implementation, which calls a getEncodingClass() function, which, in its turn, may throw an exception (line 150).

From php.net: Warning It was not possible to throw an exception from within a __toString() method prior to PHP 7.4.0. Doing so will result in a fatal error.

I think, if there is a need to keep a PHP 7.4 support, better change the line 150 somehow (for example, simply return an empty string). Note that __toString() method must return a string.

[j0k3r]

👍