? will be allowed as a wildcard by default in Scala 2.13.9 and 2.12.16

[smarter]

Previously, this was only allowed under -Xsource:3, but starting from 2.13.9 (cf scala/scala#9990) and 2.12.16 (cf scala/scala#10005) this syntax will be enabled by default, so scalameta should support it without requiring the use of Scala213Source3/Scala212Source3:

scalameta/scalameta/dialects/shared/src/main/scala/scala/meta/dialects/package.scala

Lines 55 to 59 in d21ee31

	/**
	* Dialect starting with Scala 2.13.6 for `-Xsource:3` option
	*/
	implicit val Scala213Source3 = Scala213
	.withAllowQuestionMarkPlaceholder(true)