Add table of content for instant meilisearch customization

Author: bidoubiwa

README.md

@@ -78,6 +78,13 @@ const searchClient = instantMeiliSearch(
 
 InstantMeilisearch offers some options you can set to further fit your needs.
 
+### Customization
+
+- [`placeholderSearch`]((#placeholder-search)): Enable or disable placeholder search (default: `true`).
+- [`paginationTotalHits`](#pagination-total-hits): Maximum total number of hits to create a finite pagination (default: `200`).
+- [`primaryKey`](#primary-key): Specify the primary key of your documents (default `undefined`).
+- [`keepZeroFacets`](#keep-zero-facets): Show the facets value even when they have 0 matches (default `false`).
+
 The options are added as the third parameter of the `instantMeilisearch` function
 ```js
 import { instantMeiliSearch } from '@meilisearch/instant-meilisearch'
@@ -126,7 +133,7 @@ Specify the field in your documents containing the [unique identifier](https://d
 { primaryKey : 'id' } // default: undefined
 ```
 
-### keepZeroFacets
+### Keep zero facets
 
 `keepZeroFacets` set to `true` keeps the facets even when they have 0 matching documents (default `false`).