ORDERS-7170 update customer_locale description in doc (#1045)

update customer_locale description in doc

<!-- Ticket number or summary of work -->
#
[ORDERS-7179](https://bigcommercecloud.atlassian.net/browse/ORDERS-7170)

## What changed?
<!-- Provide a bulleted list in the present tense -->
* since we support new format of customer locale validation, so update
customer_locale description for the supported format in doc

## Release notes draft
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language. Don't be too technical. Explain how the change will benefit
the merchant and link to the feature.

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* The newly-released [X feature] is now available to use. Now, you’ll be
able to [perform Y action].
* We're happy to announce [X feature], which can help you [perform Y
action].
* [X feature] helps you to create [Y response] using the [Z query
parameter]. Now, you can deliver [ex, localized shopping experiences for
your customers].
* Fixed a bug in the [X endpoint]. Now the [Y field] will appear when
you click [Z option]. -->

<img width="782" height="530" alt="Screenshot 2025-08-15 at 10 33 23 am"
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/>


## Anything else?
<!-- Add related PRs, salient notes, additional ticket numbers, etc. -->

ping @bigcommerce/team-orders

Author: YevenLourance

reference/orders.v2.oas2.yml

@@ -113,7 +113,7 @@ paths:
 
         > #### Note
         > * If historical orders processed on another eCommerce platform are being migrated to BigCommerce, supply the `external_source` field with the code **M-MIG**. This code will exclude the historical orders from the store’s GMV/order count, which factors into pricing.
-        
+
       summary: Update an Order
       tags:
         - Orders
@@ -386,7 +386,7 @@ paths:
         > #### Note
         > * If historical orders processed on another eCommerce platform are being migrated to BigCommerce, supply the `external_source` field with the code **M-MIG**. This code will exclude the historical orders from the store’s GMV/order count, which factors into pricing.
         
-        
+
       summary: Create an Order
       tags:
         - Orders
@@ -4158,8 +4158,13 @@ components:
           type: string
         customer_locale:
           type: string
-          example: en
-          description: The customer’s locale.
+          example: en, asa, en-US, es-419
+          description: |
+            The customer’s locale. The supported formats are:
+            - 2-char lowercase characters. e.g., `en`
+            - 3-char lowercase characters. e.g., `asa`
+            - 5-char the language code is 2 lowercase characters and the region code is 2 uppercase characters, with `-` in the middle. e.g., `en-US`
+            - 6-char the language code is 2 lowercase character and the region code is three digit number, with `-` in the middle. e.g., `es-419`
         external_order_id:
           type: string
           example: external-order-id
@@ -4876,8 +4881,13 @@ components:
               type: string
             customer_locale:
               type: string
-              example: en
-              description: The customer’s locale.
+              example: en, asa, en-US, es-419
+              description: |
+                The customer’s locale. The supported formats are:
+                - 2-char lowercase characters. e.g., `en`
+                - 3-char lowercase characters. e.g., `asa`
+                - 5-char the language code is 2 lowercase characters and the region code is 2 uppercase characters, with `-` in the middle. e.g., `en-US`
+                - 6-char the language code is 2 lowercase character and the region code is three digit number, with `-` in the middle. e.g., `es-419`
             external_order_id:
               type: string
               nullable: true