Fix typos / missing fields or broken mermaid diagrams for vouchers / promotions docs (#1547)

Author: krzysztofzuraw

docs/developer/discounts/promotions.mdx

@@ -39,7 +39,7 @@ The catalogue discounts from promotions are recalculated by a background task, s
 
 ### Examples of the use cases
 
-- Define the product fixed or parentage discounts based on certain conditions.
+- Define the product fixed or percentage discounts based on certain conditions.
 - Define the discount available only for a specific period.
 
 ### Order promotions
@@ -1200,6 +1200,7 @@ that applies on objects with subtotal above **$20**.
         {
           "id": "Q2hlY2tvdXRMaW5lOmU5ZmI3YjY3LTA4ZjctNDQzZi1iMWNjLWE1ZmJlNGU0NjcxMg==",
           "quantity": 2,
+          "isGift": false,
           "undiscountedTotalPrice": {
             "amount": 40.0
           },
@@ -1226,6 +1227,7 @@ that applies on objects with subtotal above **$20**.
         {
           "id": "Q2hlY2tvdXRMaW5lOmMwNzhjNGQyLWI1MzUtNDhkMy04MDlmLTA1ZDUyYjY3MWFiNQ==",
           "quantity": 1,
+          "isGift": true,
           "undiscountedTotalPrice": {
             "amount": 50.0
           },
@@ -1292,6 +1294,7 @@ After completing the checkout we get an order with the gift line:
         "lines": [
           {
             "quantity": 2,
+            "isGift": false,
             "totalPrice": {
               "gross": {
                 "amount": 40.0
@@ -1313,6 +1316,7 @@ After completing the checkout we get an order with the gift line:
           },
           {
             "quantity": 1,
+            "isGift": true,
             "totalPrice": {
               "gross": {
                 "amount": 0.0
@@ -1325,11 +1329,11 @@ After completing the checkout we get an order with the gift line:
             },
             "undiscountedUnitPrice": {
               "gross": {
-                "amount": 500.0
+                "amount": 50.0
               }
             },
             "unitDiscount": {
-              "amount": 500.0
+              "amount": 50.0
             }
           }
         ]
@@ -1359,18 +1363,18 @@ When a voucher code is added, the discount from the order promotion is not appli
 graph TD
     A(Base undiscounted price) --> B[Apply catalogue discounts]
     B --> Z{Voucher code added?}
-    Z --> |No| K[Apply `order` discount]
+    Z --> |No| K[Apply order discount]
     K --> E
-    Z --> |Yes| C[Apply lines vouchers - `ONCE_PER_ORDER`, `SPECIFIC_PRODUCT`]
-    C --> D[Apply `ENTIRE_ORDER` voucher]
+    Z --> |Yes| C[Apply lines vouchers - ONCE_PER_ORDER, SPECIFIC_PRODUCT]
+    C --> D[Apply ENTIRE_ORDER voucher]
     D --> E[Apply taxes]
 ```
 
 #### Below the chart shows the process of applying the `ORDER` promotion discount
 
 ```mermaid
 graph TD
-    A(Base discounted price) --> B[Collect all `ORDER` promotion rules that apply]
+    A(Base discounted price) --> B[Collect all order promotion rules that apply]
     B --> C[For gift promotion rules choose the available product variant from the assigned gifts, with the highest discounted price]
     C --> E[Compare the potential gift prices with other possible discounts]
     E --> F[Choose the promotion rule that gives the best saving for the user]

docs/developer/discounts/vouchers.mdx

@@ -3,7 +3,7 @@ title: Vouchers
 sidebar_label: Vouchers
 ---
 
-Vouchers are a way to apply discounts to orders. They can be used to reduce the cost of a checkout. Vouchers can be applied to the entire order
+Vouchers are a way to apply discounts to orders or they can be used to reduce the cost of a checkout. Vouchers can be applied to the entire order
 or to specific products. They can also be limited to a minimum quantity of products in the checkout. Vouchers and [promotions](developer/discounts/promotions.mdx) can be used together.
 
 :::info