When we suggest the replacement for a macro we include the "!" in the
suggested replacement but the span only contains the name of the macro
itself. Using that replacement would cause a duplicate "!" in the
resulting code.
I originally tried to extend the span to be replaced by 1 byte in
rust-lang/rust#47424. However, @zackmdavis pointed out that there can be
whitespace between the macro name and the bang.
Instead, just remove the bang from the suggested replacement.
Fixes#47418
