message: Use match instead of if-let
diff: @@ -180,10 +180,9 @@ impl<'interner, 'arena> Context<'interner> {
  RcDoc::concat([
  RcDoc::concat([
  self.plicity(*plicity),
  - if let Some(name) = param_name {
  - self.string_id(*name)
  - } else {
  - RcDoc::nil()
  + match param_name {
  + Some(name) => self.string_id(*name),
  + None => RcDoc::text("_"),
  },
  RcDoc::space(),
  RcDoc::text(":"),
  @@ -208,10 +207,9 @@ impl<'interner, 'arena> Context<'interner> {
  RcDoc::text("fun"),
  RcDoc::space(),
  self.plicity(*plicity),
  - if let Some(name) = param_name {
  - self.string_id(*name)
  - } else {
  - RcDoc::nil()
  + match param_name {
  + Some(name) => self.string_id(*name),
  + None => RcDoc::text("_"),
  },
  RcDoc::space(),
  RcDoc::text("=>"),
  