Update breaking changes section format in migration guide (dotansimha#10636)

Author: eddeee888

website/src/pages/docs/migration/operations-and-client-preset-from-5-0.mdx

@@ -209,7 +209,7 @@ const config: CodegenConfig = {
 
 ## Breaking changes
 
-1. Object types are no longer generated
+### 1. Object types are no longer generated
 
 Previously, Object types from the schema were generated via the `typescript` plugin, for example:
 
@@ -230,11 +230,11 @@ Now, Object types are no longer generated. This prevents accidental misuse of sc
 
 If you need schema types for any reason, please generate them using the `typescript` plugin in a separate file.
 
-2. Args types are no longer generated
+### 2. Args types are no longer generated
 
 Args types are only used for server use cases, so they are no longer generated for client use cases.
 
-3. Scalar types are no longer generated as a reusable type
+### 3. Scalar types are no longer generated as a reusable type
 
 Previously, Scalar types from the schema were generated into an object and reused in Variables types:
 
@@ -271,13 +271,13 @@ export type UserVariables = Exact<{
 }>
 ```
 
-4. Input and Enum types are only generated when used
+### 4. Input and Enum types are only generated when used
 
 Previously, all Input and Enum types were generated, even if they were not used. This could increase bundle size when Enums that incur runtime cost (e.g. native TypeScript enum or const enum) are used.
 
 Now, only Input and Enum types used in operations are generated.
 
-5. `__typename` is only generated when used
+### 5. `__typename` is only generated when used
 
 Previously, `__typename` fields in Result types are generated as optional by default, even when they were not requested:
 
@@ -317,7 +317,7 @@ export type UserQuery = {
   continue to use `skipTypeNameForRoot` and `nonOptionalTypename` options to configure expected type behaviours.
 </Callout>
 
-6. Document field types are generated to correctly match runtime expectations
+### 6. Document field types are generated to correctly match runtime expectations
 
 Previously, nullable fields in Result types were generated as optional by default:
 
@@ -340,7 +340,7 @@ export type UserQuery = {
 }
 ```
 
-7. Enum config options are consolidated and the default value is changed
+### 7. Enum config options are consolidated and the default value is changed
 
 Previously, there were 4 boolean options to set which Enum variant to generate. When combined, these options overrode one another, leading to unexpected and confusing behaviour.
 
@@ -354,7 +354,7 @@ Now, `enumType` is the only config option to use. The default has also been chan
 | Native const   | `export const enum UserRole { Admin = 'ADMIN', Customer = 'CUSTOMER' };`     | `{constEnums:true}`          | `{enumType:'native-const'}`           |
 | Native numeric | `export enum UserRole { Admin = 0, Customer = 1 }`                           | `{numericEnums:true}`        | `{enumType:'native-numeric'}`         |
 
-8. `avoidOptionals` option is updated to only handle Operation types
+### 8. `avoidOptionals` option is updated to only handle Operation types
 
 Previously, `avoidOptionals` was shared with the [typescript plugin](https://the-guild.dev/graphql/codegen/plugins/typescript/typescript#avoidoptionals). As a result, some inner options did not affect Operation types (such as `avoidOptionals.resolvers`, `avoidOptionals.query`, `avoidOptionals.mutation`, `avoidOptionals.subscription`).
 
@@ -366,7 +366,7 @@ Now, there are only 3 inner options, and when enabled, each forces the respectiv
 
 Note that the default is `false`, and you can still use `avoidOptionals:true` to turn on all options, without having to set each one individually.
 
-9. `preResolveTypes` option is removed
+### 9. `preResolveTypes` option is removed
 
 The `preResolveTypes` option was used to generate Result types inline (`preResolveTypes:false`) or use the ones generated by the `typescript` plugin (`preResolveTypes:true`). This approach had several drawbacks:
 
@@ -378,21 +378,21 @@ The `preResolveTypes` option was used to generate Result types inline (`preResol
 
 If you are seeing problems, please create an issue [here](https://github.com/dotansimha/graphql-code-generator/issues).
 
-10. Legacy utility types are removed
+### 10. Legacy utility types are removed
 
 The following utility types have been removed:
 
 - `Maybe`: used to handle nullability types of fields in Result types. However, field types have been pre-resolved and inlined for a long time, so this type is no longer needed.
 - `InputMaybe`: used to handle nullability types of Input. Input types are now inlined, so this type is no longer needed.
 - `MakeOptional`, `MakeMaybe` and `MakeEmpty`: used to handle `preResolveTypes:false`. However, `preResolveTypes` has been removed, so these types are no longer needed.
 
-11. Make `unknown` the default type for custom scalars instead of `any`
+### 11. Make `unknown` the default type for custom scalars instead of `any`
 
 Previously, the default custom Scalars type was `any`, which bypassed typechecking.
 
 Now, the default type is `unknown` to ensure data is handled carefully by users.
 
-12. Make `string | number` the default type for the native `ID` scalar
+### 12. Make `string | number` the default type for the native `ID` scalar
 
 Previously, one set of default Scalar types was shared between client and server plugins via the `typescript` plugin dependency. This meant it was not possible to set the default for client, as it would complicate the server config, and vice versa. See this [PR for more details](https://github.com/dotansimha/graphql-code-generator/pull/9497).