This name is consist with the rest of the setter and getter methods
in ParserOutput. Renamed the methods in OutputPage, ImageHistoryList,
ImageHistoryPseudoPager, and ContribsPager as well for consistency;
it also makes chasing down lingering references in codesearch easier.
Soft-deprecated the old name for 1.38. Hard-deprecation will follow,
but there are a number of users in production that should be chased
down first.
Code search:
https://codesearch.https://codesearch.wmcloud.org/deployed/?q=(allow%7Cprevent)Clickjacking&i=nope&files=&excludeFiles=&repos=
Bug: T287216
Change-Id: I9822c60c180d204bd30cb4447a1120155d456da4
df3cc40fac