Update docs for Custom Select props (#5776)

Author: lukebennett88

docs/pages/typescript/index.tsx

@@ -91,7 +91,12 @@ The \`actionMeta\` parameter is optional. \`ActionMeta\` is a union that is disc
 You can use module augmentation to add custom props to the \`Select\` prop types:
 
 ~~~jsx
-declare module 'react-select/dist/declarations/src/Select' {
+import type {} from 'react-select/base';
+// This import is necessary for module augmentation.
+// It allows us to extend the 'Props' interface in the 'react-select/base' module
+// and add our custom property 'myCustomProp' to it.
+
+declare module 'react-select/base' {
   export interface Props<
     Option,
     IsMulti extends boolean,