Add missing article

Author: elharo

presto-docs/src/main/sphinx/language/types.rst

@@ -249,7 +249,7 @@ Example: ``MAP(ARRAY['foo', 'bar'], ARRAY[1, 2])``
 ^^^^^^^
 
 A structure made up of named fields. The fields may be of any SQL type, and are
-accessed with field reference operator ``.``
+accessed with the field reference operator ``.``
 
 Example: ``CAST(ROW(1, 2.0) AS ROW(x BIGINT, y DOUBLE))``
 
@@ -447,4 +447,4 @@ The types support operations such as spatial measurements and relationship check
 crucial for geographic information systems (GIS) and other applications requiring spatial data manipulation.
 The geospatial types ensure data integrity and provide robust tools for complex spatial querying and analysis.
 
-See :doc:`/functions/geospatial`.
+See :doc:`/functions/geospatial`.