Port #[link_section] to the new attribute parsing infrastructure

compiler/rustc_attr_data_structures/src/attributes.rs

@@ -256,6 +256,9 @@ pub enum AttributeKind {
     /// Represents `#[link_name]`.
     LinkName { name: Symbol, span: Span },
 
+    /// Represents [`#[link_section]`](https://doc.rust-lang.org/reference/abi.html#the-link_section-attribute)
+    LinkSection { name: Symbol, span: Span },
+
     /// Represents `#[loop_match]`.
     LoopMatch(Span),
 

compiler/rustc_attr_data_structures/src/encode_cross_crate.rs

@@ -24,6 +24,7 @@ impl AttributeKind {
             DocComment { .. } => Yes,
             ExportName { .. } => Yes,
             Inline(..) => No,
+            LinkSection { .. } => No,
             MacroTransparency(..) => Yes,
             Repr(..) => No,
             Stability { .. } => Yes,