fix: Allow backlinks to work with fully qualified urls and anchors (#4050)

closes #4048

server/utils/parseDocumentIds.test.ts

@@ -3,14 +3,21 @@ import parseDocumentIds from "./parseDocumentIds";
 it("should not return non links", () => {
   expect(parseDocumentIds(`# Header`).length).toBe(0);
 });
+
 it("should return an array of document ids", () => {
   const result = parseDocumentIds(`# Header
   
-  [internal](/doc/test-456733)
+  [internal](http://app.getoutline.com/doc/test-456733)
+
+  More text 
+
+  [internal](/doc/test-123456#heading-anchor)
   `);
-  expect(result.length).toBe(1);
+  expect(result.length).toBe(2);
   expect(result[0]).toBe("test-456733");
+  expect(result[1]).toBe("test-123456");
 });
+
 it("should not return duplicate document ids", () => {
   expect(parseDocumentIds(`# Header`).length).toBe(0);
   const result = parseDocumentIds(`# Header
@@ -22,9 +29,11 @@ it("should not return duplicate document ids", () => {
   expect(result.length).toBe(1);
   expect(result[0]).toBe("test-456733");
 });
+
 it("should not return non document links", () => {
   expect(parseDocumentIds(`[google](http://www.google.com)`).length).toBe(0);
 });
+
 it("should not return non document relative links", () => {
   expect(parseDocumentIds(`[relative](/developers)`).length).toBe(0);
 });