style(rust): drop declaration ordering rule

src/skills/style/rust/rules/declarations.md

@@ -1,14 +0,0 @@
-# Declaration rules
-
-## Order declarations by use
-
-### Rule
-
-Order related Rust declarations from the type that uses other local types to those local dependencies.
-For a type with multiple local field dependencies, place dependencies in field order.
-Apply the rule depth-first before moving to the next dependency.
-
-### Rationale
-
-Use-first order lets readers start with the public or owning shape.
-They can then read supporting types in the order the owner references them.