Move the MWLogger PSR-3 logging related classes into the
MediaWiki\Logger namespace. Create shim classes to ease migration of
existing MWLoggerFactory usage to the namespaced classes.
Bug: T93406
Change-Id: I359cc81fbd2dcf8937742311dcc7d3dee08747b0
Swapped some "$var type" to "type $var" or added missing types
before the $var. Changed some other types to match the more common
spelling. Makes beginning of some text in captial.
Change-Id: I8c9f30128b46086064326708a4878228ba459447
