allow import language.3.1

[bishabosha]

Compiler version

3.1.0

Minimized example

import language.`3.1`

Output

./test.scala:1:17: value 3.1 is not a member of object language - did you mean language.3.0?
import language.`3.1`
                ^^^^^

Expectation

it should work, this seems to have been overlooked in #13617

However since 3.1.0 is released I guess this can't happen until a hypothetical Scala 3.2