use {:?} not {:#?}

Since the same feature has been added to gstd (gear-tech/gear#3610)
this crate should've been deprecated

However, the compact version of dbg! proposed in rust-lang/rust#82778
does look better

So let me repurpose this crate as the compact implementation of dbg! for gear smart contracts

lib.rs

@@ -21,7 +21,7 @@ macro_rules! dbg {
             // of temporaries - https://stackoverflow.com/a/48732525/1063961
             match $val {
                 tmp => {
-                    gstd::debug!("[{}:{}] {} = {:#?}",
+                    gstd::debug!("[{}:{}] {} = {:?}",
                         gstd::prelude::file!(),
                         gstd::prelude::line!(),
                         gstd::prelude::stringify!($val),