Update _overviews/core/collections-migration-213.md

Co-Authored-By: Dale Wijnand <344610+dwijnand@users.noreply.github.com>

Author: eed3si9n

_overviews/core/collections-migration-213.md

@@ -53,7 +53,7 @@ In the future when your API is able to break the source compatibility, it might
 import scala.collection.immutable.Seq
 ~~~
 
-Note that in Scala 2.13 the sequence passed into a vararg as `orderFood(xs: _*)` must also be immutable. This is because the sequence passed into a vararg must conform to`scala.Seq` acoording to [Specification](https://www.scala-lang.org/files/archive/spec/2.12/06-expressions.html#function-applications). Thus if your API exposes varargs, it will be an unavoidable breaking change. This might affect Java interoperability.
+Note that in Scala 2.13 the sequence passed into as a varargs as `orderFood(xs: _*)` must also be immutable. This is because the sequence passed in as a varargs must conform to `scala.Seq` according to [SLS 6.6](https://www.scala-lang.org/files/archive/spec/2.12/06-expressions.html#function-applications). Thus, if your API exposes varargs it will be an unavoidable breaking change. This might affect Java interoperability.
 
 ## What are the breaking changes?
 
@@ -260,4 +260,4 @@ Examples of libraries that cross-compile with separate source directories:
 To learn about differences when implementing custom collection types or operations, see the following documents:
   - [The architecture of Scala collections]({{ site.baseurl }}/overviews/core/architecture-of-scala-213-collections.html)
   - [Implementing custom collections]({{ site.baseurl }}/overviews/core/custom-collections.html)
-  - [Adding custom collection operations]({{ site.baseurl }}/overviews/core/custom-collection-operations.html)
+  - [Adding custom collection operations]({{ site.baseurl }}/overviews/core/custom-collection-operations.html)