fix: throw NotFoundError when a document cannot be found

[angeloashmore]

Types of changes

• Chore (a non-breaking change which is related to package maintenance)
• Bug fix (a non-breaking change which fixes an issue)
• New feature (a non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Description

This PR fixes getFirst() and all dependent methods, including getByUID() and getByID(), by throwing a NotFoundError when a matching document is not found.

NotFoundError is a subclass of PrismicError, retaining compatibility with instanceof PrismicError.

Before:

import { createClient } from "@prismicio/client";

const client = createClient("example-prismic-repo");
await client.getByUID("page", "non-existent");
// => throws PrismicError

After:

import { createClient } from "@prismicio/client";

const client = createClient("example-prismic-repo");
await client.getByUID("page", "non-existent");
// => throws NotFoundError

Checklist:

• My change requires an update to the official documentation.
• All TSDoc comments are up-to-date and new ones have been added where necessary.
• All new and existing tests are passing.

🦁

[codecov-commenter]

Codecov Report

Merging #316 (e002238) into master (76fa2ca) will not change coverage.
The diff coverage is 100.00%.

❗ Your organization is not using the GitHub App Integration. As a result you may experience degraded service beginning May 15th. Please install the Github App Integration for your organization. Read more.

@@           Coverage Diff           @@
##           master     #316   +/-   ##
=======================================
  Coverage   99.96%   99.96%           
=======================================
  Files          50       50           
  Lines        6045     6045           
  Branches      294      294           
=======================================
  Hits         6043     6043           
  Misses          2        2           

Files Changed	Coverage Δ
src/createClient.ts	100.00% <100.00%> (ø)

[lihbr]

LGTM :) Easy one!