message: Split up appending of fragments to query document
  Splits the appending of fragments to the query document into separate
  sub expressions to fix an issue where a query with lots of fragments
  caused the Swift type checker to fail.
diff: @@ -262,17 +262,20 @@ export class SwiftAPIGenerator extends SwiftGenerator<CompilerContext> {
  if (fragmentsReferenced.size > 0) {
  this.printNewlineIfNeeded();
  + this.printOnNewline(swift`public var queryDocument: String`);
  + this.withinBlock(() => {
  this.printOnNewline(
  - swift`public var queryDocument: String { return operationDefinition`
  + swift`var document: String = operationDefinition`
  );
  fragmentsReferenced.forEach(fragmentName => {
  - this.print(
  - swift`.appending("\\n" + ${this.helpers.structNameForFragmentName(
  + this.printOnNewline(
  + swift`document.append("\\n" + ${this.helpers.structNameForFragmentName(
  fragmentName
  )}.fragmentDefinition)`
  );
  });
  - this.print(swift` }`);
  + this.printOnNewline(swift`return document`);
  + });
  }
  this.printNewlineIfNeeded();
  