Fixup all doxygen warnings

No idea why the operator<<() functions have started moaning now.

Change-Id: I338b96c53888f4ddb8e42283a6dcda7708e567f0
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/47431
Commit-Queue: Ben Clayton <bclayton@google.com>
Reviewed-by: Antonio Maiorano <amaiorano@google.com>
diff --git a/src/semantic/member_accessor_expression.h b/src/semantic/member_accessor_expression.h
index 4865b77..2f98821 100644
--- a/src/semantic/member_accessor_expression.h
+++ b/src/semantic/member_accessor_expression.h
@@ -58,6 +58,7 @@
   /// Constructor
   /// @param declaration the AST node
   /// @param type the resolved type of the expression
+  /// @param statement the statement that owns this expression
   /// @param member the structure member
   StructMemberAccess(ast::MemberAccessorExpression* declaration,
                      type::Type* type,
@@ -81,6 +82,7 @@
   /// Constructor
   /// @param declaration the AST node
   /// @param type the resolved type of the expression
+  /// @param statement the statement that
   /// @param indices the swizzle indices
   Swizzle(ast::MemberAccessorExpression* declaration,
           type::Type* type,