message: remove some unneeded lifetime parameters
  Makes the compiler example read better.
diff: @@ -28,7 +28,7 @@ pub trait Compiler: Interner {
  /// dolor,sit,amet,
  /// consectetur,adipiscing,elit
  /// ```
  -fn all_classes<'d>(db: &(dyn Compiler + 'd)) -> Arc<Vec<Class>> {
  +fn all_classes(db: &dyn Compiler) -> Arc<Vec<Class>> {
  let string = db.input_string();
  let rows = string.split('\n');
  @@ -53,13 +53,13 @@ fn all_classes<'d>(db: &(dyn Compiler + 'd)) -> Arc<Vec<Class>> {
  Arc::new(classes)
  }
  -fn fields<'d>(db: &(dyn Compiler + 'd), class: Class) -> Arc<Vec<Field>> {
  +fn fields(db: &dyn Compiler, class: Class) -> Arc<Vec<Field>> {
  let class = db.lookup_intern_class(class);
  let fields = class.fields.clone();
  Arc::new(fields)
  }
  -fn all_fields<'d>(db: &(dyn Compiler + 'd)) -> Arc<Vec<Field>> {
  +fn all_fields(db: &dyn Compiler) -> Arc<Vec<Field>> {
  Arc::new(
  db.all_classes()
  .iter()
  