PHP 8.5 migration guide

[mumumu]

Based on PHP 8.5 UPGRADE NOTES and past migration guides.

• TODO
  • New Features
  • New Classes and Interfaces
  • New Functions
  • New Global Constants
  • Backward Incompatible Changes
  • Deprecated Features
  • Windows Support
  • Other Changes
  • doc-base/manual.xml.in change
    • added PHP 8.5 migration guide link doc-base#258

[DanielEScherzer]

I forgot to add UPGRADING for FILTER_THROW_ON_FAILURE and the 2 new classes that added, so it wasn't in #4886 originally - I just added that, can you include them here too?

[TimWolla]

php/php-src#20239 might also need to be incorporated

[mumumu]

I forgot to add UPGRADING for FILTER_THROW_ON_FAILURE and the 2 new classes that added, so it wasn't in #4886 originally

Added in 4f86bb5

php/php-src#20239 might also need to be incorporated

Changed in 3d7f6f5

[TimWolla]

php/php-src#20278

[mumumu]

php/php-src#20278

Added in a288458.
However, it is not the UPGRADING file as-is; instead, content based on the RFC wording has been added.