improve wording (opensearch-project#6445)

the mapping actually *defines* the field types, it doesn't just "correspond to" them.

Signed-off-by: Stavros Macrakis <[email protected]>

Author: smacrakis

_field-types/index.md

@@ -12,7 +12,7 @@ redirect_from:
 
 # Mappings and field types
 
-You can define how documents and their fields are stored and indexed by creating a _mapping_. The mapping specifies the list of fields for a document. Every field in the document has a _field type_, which corresponds to the type of data the field contains. For example, you may want to specify that the `year` field should be of type `date`. To learn more, see [Supported field types]({{site.url}}{{site.baseurl}}/field-types/supported-field-types/index/).
+You can define how documents and their fields are stored and indexed by creating a _mapping_. The mapping specifies the list of fields for a document. Every field in the document has a _field type_, which defines the type of data the field contains. For example, you may want to specify that the `year` field should be of type `date`. To learn more, see [Supported field types]({{site.url}}{{site.baseurl}}/field-types/supported-field-types/index/).
 
 If you're just starting to build out your cluster and data, you may not know exactly how your data should be stored. In those cases, you can use dynamic mappings, which tell OpenSearch to dynamically add data and its fields. However, if you know exactly what types your data falls under and want to enforce that standard, then you can use explicit mappings.
 
@@ -219,4 +219,4 @@ The response contains the specified fields:
     }
   }
 }
-```
+```