fix some typo in TypeTest doc

library/src/scala/reflect/TypeTest.scala

@@ -1,18 +1,19 @@
 package scala.reflect
 
-/** A `TypeTest[S, T] contains the logic needed to know at runtime if a value of
+/** A `TypeTest[S, T]` contains the logic needed to know at runtime if a value of
  *  type `S` is an instance of `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:
+ *  the pattern is one of the following forms:
  *    - `t: T`
- *    - `t @ X()` where the `X.unapply` has takes an argument of type `T`
+ *    - `t @ X()` where `X.unapply` takes an argument of type `T`
  *  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 if and only if S of type T.
+  /** A `TypeTest[S, T]` can serve as an extractor that matches if and only if a value of type `S` is
+   *  an instance of `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 `tt` is the `TypeTest[S, T]` instance.