feat(edgedb_codegen_core): add prettyplease format option

output of `rustfmt` is dependent on the version of rust used and not good for tests.

Cargo.toml

@@ -27,6 +27,7 @@ insta = "1"
 log = "0.4"
 num-bigint = "0.4"
 num-traits = "0.2"
+prettyplease = "0.2"
 proc-macro2 = "1"
 quote = "1"
 rstest = "0.22"

crates/edgedb_codegen_core/Cargo.toml

@@ -19,6 +19,7 @@ edgedb-protocol = { workspace = true, features = ["all-types", "with-serde"] }
 edgedb-tokio = { workspace = true, features = ["unstable", "derive"] }
 heck = { workspace = true }
 log = { workspace = true }
+prettyplease = { workspace = true }
 proc-macro2 = { workspace = true }
 quote = { workspace = true }
 syn = { workspace = true }

crates/edgedb_codegen_core/src/utils.rs

@@ -41,6 +41,7 @@ pub fn resolve_path(path: impl AsRef<Path>, error_span: Span) -> syn::Result<Pat
 	Ok(base_dir_path.join(path))
 }
 
+/// Will format the given source code using `rustfmt`.
 pub async fn rustfmt(source: &str) -> std::io::Result<String> {
 	let mut process = Command::new("rustfmt")
 		.args(["--emit", "stdout"])
@@ -57,3 +58,8 @@ pub async fn rustfmt(source: &str) -> std::io::Result<String> {
 		std::io::Error::new(std::io::ErrorKind::InvalidData, "Rustfmt output not UTF-8")
 	})
 }
+
+/// Will format the given source code using `prettyplease`.
+pub fn prettify(source: &str) -> syn::Result<String> {
+	Ok(prettyplease::unparse(&syn::parse_str(source)?))
+}