Fix typos

Author: nicolasstucki

docs/docs/reference/other-new-features/type-test.md

@@ -6,7 +6,7 @@ title: "TypeTest"
 TypeTest
 --------
 
-`TypeTest` provides the a replacement for `ClassTag.unapply` where the type of the argument is generalized.
+`TypeTest` provides a replacement for `ClassTag.unapply` where the type of the argument is generalized.
 `TypeTest.unapply` will return `Some(x.asInstanceOf[Y])` if `x` conforms to `Y`, otherwise it returns `None`.
 
 ```scala
@@ -15,7 +15,7 @@ trait TypeTest[-S, T] extends Serializable {
 }
 ```
 
-Just like `ClassTag` used to to, it can be used to perform type checks in patterns.
+Just like `ClassTag` used to do, it can be used to perform type checks in patterns.
 
 ```scala
 type X

library/src/scala/reflect/TypeTest.scala

@@ -1,23 +1,21 @@
 package scala.reflect
 
 /** A `TypeTest[S, T] contains the logic needed to know at runtime if a value of
- *  type `S` can be downcased to `T`.
+ *  type `S` can be downcasted to `T`.
  *
  *  If a pattern match is performed on a term of type `s: S` that is uncheckable with `s.isInstanceOf[T]` and
  *  the pattern are of the form:
  *    - `t: T`
  *    - `t @ X()` where the `X.unapply` has takes an argument of type `T`
- *  then a given instance of `TypeTest[S, T]` is summoned and used to performed the test.
- *
- *  Note: This is replacemet for `ClassTag.unapply` that can be sound for path dependent types
+ *  then a given instance of `TypeTest[S, T]` is summoned and used to perform the test.
  */
 @scala.annotation.implicitNotFound(msg = "No TypeTest available for [${S}, ${T}]")
 trait TypeTest[-S, T] extends Serializable {
 
   /** A TypeTest[S, T] can serve as an extractor that matches only S of type T.
    *
    * The compiler tries to turn unchecked type tests in pattern matches into checked ones
-   * by wrapping a `(_: T)` type pattern as `tt(_: T)`, where `ct` is the `TypeTest[S, T]` instance.
+   * by wrapping a `(_: T)` type pattern as `tt(_: T)`, where `tt` is the `TypeTest[S, T]` instance.
    * Type tests necessary before calling other extractors are treated similarly.
    * `SomeExtractor(...)` is turned into `tt(SomeExtractor(...))` if `T` in `SomeExtractor.unapply(x: T)`
    * is uncheckable, but we have an instance of `TypeTest[S, T]`.