This is a simple naming change PR, to fix the fact that "metadata" is a
single English word, and for too long we have not followed general
naming conventions for it. We are also not consistent about it, for
example, METADATA instead of META_DATA if we were trying to be
consistent with MetaData (although METADATA is correct when considered
in the context of "metadata"). This was a simple find and replace across
the code base, only taking a few minutes to fix this naming issue
forever.
The joda to java.time migration requires users to upgrade their mappings. We allow them to still use 6.x created indices with joda patterns in 7 but ask them to upgrade their patterns in 7.x.
This migration guide is to help them understand how they could be affected and what needs to be changed in their mappings.
closes#51614closes#51236
