fix(interfaces): [Point] ensure offset is a number

Signed-off-by: Lexus Drumgold <[email protected]>

Author: unicornware

src/interfaces/__tests__/point.spec-d.ts

@@ -10,4 +10,8 @@ describe('unit-d:interfaces/Point', () => {
   it('should extend Required<unist.Point>', () => {
     expectTypeOf<TestSubject>().toMatchTypeOf<Required<unist.Point>>()
   })
+
+  it('should match [offset: number]', () => {
+    expectTypeOf<TestSubject>().toHaveProperty('offset').toBeNumber()
+  })
 })

src/interfaces/point.ts

@@ -14,6 +14,11 @@ import type unist from 'unist'
  *
  * @extends {Required<unist.Point>}
  */
-interface Point extends Required<unist.Point> {}
+interface Point extends Required<unist.Point> {
+  /**
+   * Index of character in a source file (0-indexed integer).
+   */
+  offset: number
+}
 
 export type { Point as default }