[Vega] Add Filter custom label for opensearchDashboardsAddFilter

Signed-off-by: Aswath <it.aswath@gmail.com>

Co-authored-by: Josh Romero <rmerqg@amazon.com>

src/plugins/vis_type_vega/public/vega_view/vega_base_view.js

@@ -315,7 +315,7 @@ export class VegaBaseView {
  /**
  * @param {object} query Query DSL snippet, as used in the query DSL editor
  * @param {string} [index] as defined in OpenSearch Dashboards, or default if missing
- * @param {string} alias OpenSearch Query DSL's Custom label for opensearchDashboardsAddFilter, as used in '+ Add Filter'
+ * @param {string} alias OpenSearch Query DSL's custom label for `opensearchDashboardsAddFilter`, as used in '+ Add Filter'
  */
  async addFilterHandler(query, index, alias) {
  const indexId = await this.findIndex(Utils.handleNonStringIndex(index));