Change CAUTION to WARNING in GraphQL doc

doc/api/graphql/reference/index.md

@@ -13,7 +13,7 @@ The API can be explored interactively using the [GraphiQL IDE](../index.md#graph
 Each table below documents a GraphQL type. Types match loosely to models, but not all
 fields and methods on a model are available via GraphQL.
 
-CAUTION: **Caution:**
+WARNING:
 Fields that are deprecated are marked with **{warning-solid}**.
 Items (fields, enums, etc) that have been removed according to our [deprecation process](../index.md#deprecation-process) can be found
 in [Removed Items](../removed_items.md).

lib/gitlab/graphql/docs/templates/default.md.haml

@@ -12,7 +12,7 @@
   Each table below documents a GraphQL type. Types match loosely to models, but not all
   fields and methods on a model are available via GraphQL.
 
-  CAUTION: **Caution:**
+  WARNING:
   Fields that are deprecated are marked with **{warning-solid}**.
   Items (fields, enums, etc) that have been removed according to our [deprecation process](../index.md#deprecation-process) can be found
   in [Removed Items](../removed_items.md).