message: style(compiler): fix up grammar in error message
  closes
  PR Close
diff: @@ -993,7 +993,7 @@ export class CompileMetadataResolver {
  providerMeta = new cpl.ProviderMeta(provider, {useClass: provider});
  } else if (provider === void 0) {
  this._reportError(syntaxError(
  - `Encountered undefined provider! Usually this means you have a circular dependencies (might be caused by using 'barrel' index.ts files.`));
  + `Encountered undefined provider! Usually this means you have a circular dependencies. This might be caused by using 'barrel' index.ts files.`));
  return;
  } else {
  const providersInfo =
  