minor #3027 Add information for when `filter` filter was added in 2.x branch (YetiCGN)
minor #3027 Add information for when `filter` filter was added in 2.x branch (YetiCGN)

This PR was submitted for the 2.x branch but it was merged into the 1.x branch instead (closes #3027).

Discussion
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Add information for when `filter` filter was added in 2.x branch

The current "versionadded" info can be confusing to developers, if they assume 2.9 > 1.41 and don't know that 1.x and 2.x branches are still developed simultaneously.

Commits
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a05da6db Add information for when `filter` filter was added in 2.x branch

nicolas-grekas/Twig,nicolas-grekas/Twig,nicolas-grekas/Twig,twigphp/Twig,twigphp/Twig,nicolas-grekas/Twig,nicolas-grekas/Twig,twigphp/Twig