Remove reference to `not_analyzed`.
Relates
@@ -81,7 +81,7 @@ Defaults to `true`.
<<mapping-index,`index`>>::
- Should the field be searchable? Accepts `not_analyzed` (default) and `no`.
+ Should the field be searchable? Accepts `true` (default) and `false`.
<<null-value,`null_value`>>::
