Updated unique docs

pkg/yqlib/doc/operators/headers/unique.md

@@ -1,3 +1,4 @@
 # Unique
 
-This is used to filter out duplicated items in an array.
+This is used to filter out duplicated items in an array. Note that the original order of the array is maintained.
+

pkg/yqlib/doc/operators/unique.md

@@ -9,10 +9,12 @@ Note that versions prior to 4.18 require the 'eval/e' command to be specified.&#
 {% endhint %}
 
 ## Unique array of scalars (string/numbers)
+Note that unique maintains the original order of the array.
+
 Given a sample.yml file of:
 ```yaml
-- 1
 - 2
+- 1
 - 3
 - 2
 ```
@@ -22,8 +24,8 @@ yq 'unique' sample.yml
 ```
 will output
 ```yaml
-- 1
 - 2
+- 1
 - 3
 ```