message: no space & error message correction
diff: @@ -186,7 +186,7 @@ export async function save<T extends Principal>(principal: Omit<T, 'id' | 'href'
  // Update user
  if (!isIdentityValid(principal.identity)) {
  - throw new UnprocessableEntity('Identity must include mailto:');
  + throw new UnprocessableEntity('Identity must be a valid URI');
  }
  const query = 'UPDATE principals SET ? WHERE id = ?';
  @@ -257,7 +257,7 @@ export function recordToModel(user: PrincipalRecord): Principal {
  export function isIdentityValid(identity: string): boolean {
  - const regex = /^(?:[A-Za-z]+:)?/;
  + const regex = /^(?:[A-Za-z]+:+\S*$)?/;
  return regex.test(identity);
  }
  