refactor: Move #![forbid(unsafe_code)] attributes up

What's forbidden is more important than which clippy lints are
ignored and more important directives should come first.

src/lib.rs

@@ -4,6 +4,7 @@
 //! and subject to change drastically.
 //!
 //! [Ruff]: https://github.com/charliermarsh/ruff
+#![forbid(unsafe_code)]
 #![allow(
     clippy::collapsible_else_if,
     clippy::collapsible_if,
@@ -16,7 +17,6 @@
     clippy::similar_names,
     clippy::too_many_lines
 )]
-#![forbid(unsafe_code)]
 
 mod ast;
 mod autofix;