fix spelling

Author: mjreno

docs/dev/dfn-schema-plan.md

@@ -344,7 +344,7 @@ Type `integer`.
 
 ###### `time_series`
 
-`bool = False`. Marks fields where the parser accepts either a numeric literal or a time-series name (referencing a `utl-ts` object). Not inferrable from structural type. Also appears on array fields (where it references a `utl-tas` object instead). Note that `utl-tas` currently only works with layered arrays, not full-grid arrays, though generalizing has been considered.
+`bool = False`. Marks fields where the parser accepts either a numeric literal or a time-series name (referencing a `utl-ts` object). Not inferable from structural type. Also appears on array fields (where it references a `utl-tas` object instead). Note that `utl-tas` currently only works with layered arrays, not full-grid arrays, though generalizing has been considered.
 
 ###### `pk`
 
@@ -370,7 +370,7 @@ Type `double`.
 
 ###### `time_series`
 
-`bool = False`. Marks fields where the parser accepts either a numeric literal or a time-series name (referencing a `utl-ts` object). Not inferrable from structural type. Also appears on array fields (where it references a `utl-tas` object instead). Note that `utl-tas` currently only works with layered arrays, not full-grid arrays, though generalizing has been considered.
+`bool = False`. Marks fields where the parser accepts either a numeric literal or a time-series name (referencing a `utl-ts` object). Not inferable from structural type. Also appears on array fields (where it references a `utl-tas` object instead). Note that `utl-tas` currently only works with layered arrays, not full-grid arrays, though generalizing has been considered.
 
 #### Path