[RFC] Saner numeric strings

Greetings internal, While reviving the "Permit trailing whitespace in numeric strings" RFC [1] I didn't see Nikita's comment on Andrea's original PR which commented on the fact that we should get rid of the "leading-numeric string" concept. Therefore, mostly due to time constraints, I've merge the trailing whitespace RFC with the removal of this concept in the following RFC: https://wiki.php.net/rfc/saner-numeric-strings The main gist is to convert all E_NOTICEs “A non well formed numeric value encountered” to the usual E_WARNING “A non-numeric value encountered” and allow trailing whitespaces, which would be most reasonables cases where the E_NOTICE has been emitted. This RFC is heavily based on Andrea's original RFC [1] and I would like to thank her once more for the preliminary work she's done that I could reuse. Best regards George P. Banyard [1] https://wiki.php.net/rfc/trailing_whitespace_numerics