MagicHash literals can be negative

Summary

The MagicHash section of GHC user's guide states

In general, any Haskell integer lexeme followed by a # is an Int# literal, e.g. -0x3A# as well as 32#.

But the given -0x3A# literal is not a valid Haskell integer lexeme, not without the NegativeLiterals extension. So the sentence is contradictory when read literally.

Proposed improvements or changes

Add a clarification:

MagicHash numeric literals can be negative even in the absence of the NegativeLiterals extension.