chore(docs): correction that unique preserves the original order (#433)

Author: ronen

docs/array/unique.mdx

@@ -8,7 +8,7 @@ since: 12.1.0
 
 Given an array of items -- and optionally, a function to determine their identity -- return a new array without any duplicates.
 
-The function does not preserve the original order of items.
+The function preserves the original order of items, keeping the first occurence and omitting duplicates.
 
 ```ts
 import * as _ from 'radashi'
@@ -26,8 +26,8 @@ const fish = [
   },
   {
     name: 'Salmon',
-    weight: 22,
-    source: 'river',
+    weight: 23,
+    source: 'stream',
   },
 ]
 

tests/array/unique.test.ts

@@ -9,9 +9,9 @@ describe('unique', () => {
   test('uses key fn to correctly remove duplicate items', () => {
     const list = [
       { id: 'a', word: 'hello' },
-      { id: 'a', word: 'hello' },
-      { id: 'b', word: 'oh' },
+      { id: 'a', word: 'goodbye' },
       { id: 'b', word: 'oh' },
+      { id: 'b', word: 'no' },
       { id: 'c', word: 'yolo' },
     ]
     const result = _.unique(list, x => x.id)