Get rid of warnings about unused manifest keys

Author: martindisch

swc/Cargo.toml

@@ -6,10 +6,13 @@ edition = "2021"
 [lib]
 crate-type = ["cdylib"]
 
-# [profile.release]
-codegen-units = 1
-lto = true
-opt-level = "s"
+[profile.release]
+# Uncomment to achieve smallest possible binary size (may require more experimentation).
+# Disclaimer: measure effects on runtime, results can be surprising.
+# strip = "debuginfo"
+# codegen-units = 1
+# lto = true
+# opt-level = "z"
 
 [dependencies]
 anyhow = "1.0.53"