Remove trailing semicolon from macro expression

[mesaugat]

Trailing semicolon in macro expression is being phased out.

The Rust compiler rustc 1.64.0 (a55dd71d5 2022-09-19) gives the following warning when compiling this code.

warning: trailing semicolon in macro used in expression position
  --> macro.rs:6:27
   |
6  |         println!("Hello!");
   |                           ^
...
12 |     say_hello!()
   |     ------------ in this macro invocation
   |
   = note: `#[warn(semicolon_in_expressions_from_macros)]` on by default
   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
   = note: for more information, see issue #79813 <https://github.com/rust-lang/rust/issues/79813>
   = note: macro invocations at the end of a block are treated as expressions
   = note: to ignore the value produced by the macro, add a semicolon after the invocation of `say_hello`
   = note: this warning originates in the macro `say_hello` (in Nightly builds, run with -Z macro-backtrace for more info)

warning: 1 warning emitted

[rustbot]

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[rustbot]

Thanks for the pull request, and welcome! The Rust team is excited to review your changes, and you should hear from @marioidival (or someone else) soon.