docs: filterOptions anchor link fix (#12883)

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### What?

Fixes anchor links leading to
[`filterOptions`](https://payloadcms.com/docs/fields/select#filteroptions)

### How?

Replaced camel case with lower case.

Author: anatolykopyl

docs/fields/select.mdx

@@ -54,7 +54,7 @@ export const MySelectField: Field = {
 | **`enumName`**         | Custom enum name for this field when using SQL Database Adapter ([Postgres](/docs/database/postgres)). Auto-generated from name if not defined.                                                                                                                                                         |
 | **`dbName`**           | Custom table name (if `hasMany` set to `true`) for this field when using SQL Database Adapter ([Postgres](/docs/database/postgres)). Auto-generated from name if not defined.                                                                                                                           |
 | **`interfaceName`**    | Create a top level, reusable [Typescript interface](/docs/typescript/generating-types#custom-field-interfaces) & [GraphQL type](/docs/graphql/graphql-schema#custom-field-schemas).                                                                                                                     |
-| **`filterOptions`**    | Dynamically filter which options are available based on the user, data, etc. [More details](#filterOptions)                                                                                                                                                                                             |
+| **`filterOptions`**    | Dynamically filter which options are available based on the user, data, etc. [More details](#filteroptions)                                                                                                                                                                                             |
 | **`typescriptSchema`** | Override field type generation with providing a JSON schema                                                                                                                                                                                                                                             |
 | **`virtual`**          | Provide `true` to disable field in the database, or provide a string path to [link the field with a relationship](/docs/fields/relationship#linking-virtual-fields-with-relationships). See [Virtual Fields](https://payloadcms.com/blog/learn-how-virtual-fields-can-help-solve-common-cms-challenges) |
 

docs/query-presets/overview.mdx

@@ -207,4 +207,4 @@ const config = buildConfig({
 })
 ```
 
-The `filterConstraints` function receives the same arguments as [`filterOptions`](../fields/select#filterOptions) in the [Select field](../fields/select).
+The `filterConstraints` function receives the same arguments as [`filterOptions`](../fields/select#filteroptions) in the [Select field](../fields/select).