Update existential-types.md

Author: JimVanHorn

docs/docs/reference/dropped/existential-types.md

@@ -6,15 +6,15 @@ title: Dropped: Existential Types
 Existential types using `forSome` have been dropped. The reasons for dropping them were:
 
  - Existential types violate a type soundness principle on which DOT
-   and Dotty are constructed. That principle says that every the
+   and Dotty are constructed. That principle says that every
    prefix (`p`, respectvely `S`) of a type selection `p.T` or `S#T`
    must either come from a value constructed at runtime or refer to a
    type that is known to have only good bounds.
 
  - Existential types create many difficult feature interactions
    with other Scala constructs.
 
- - Existential types have large overlap with path-dependent types,
+ - Existential types largely overlap with path-dependent types,
    so the gain of having them is relatively minor.
 
 Existential types that can be expressed using only wildcards (but not
@@ -29,5 +29,4 @@ of `Int`.
 
 When reading classfiles compiled with _scalac_, Dotty will do a best
 effort to approximate existential types with its own types. It will
-issue a warning is a precise emulation is not possible.
-
+issue a warning that a precise emulation is not possible.