Update seqs.md

Corrected distinctBy example result. -jvh

Author: JimVanHorn

_overviews/collections-2.13/seqs.md

@@ -73,7 +73,7 @@ If a sequence is mutable, it offers in addition a side-effecting `update` method
 |  `xs intersect ys`	    |The multi-set intersection of sequences `xs` and `ys` that preserves the order of elements in `xs`.|
 |  `xs diff ys`	    	    |The multi-set difference of sequences `xs` and `ys` that preserves the order of elements in `xs`.|
 |  `xs.distinct`	    |A subsequence of `xs` that contains no duplicated element.|
-|  `xs distinctBy f`	    |A subsequence of `xs` that contains no duplicated element after applying the transforming function `f`. For instance, `List("foo", "bar", "quux").distinctBy(_.length) == List("foo", "bar")`|
+|  `xs distinctBy f`	    |A subsequence of `xs` that contains no duplicated element after applying the transforming function `f`. For instance, `List("foo", "bar", "quux").distinctBy(_.length) == List("foo", "quux")`|
 
 Trait [Seq](http://www.scala-lang.org/api/current/scala/collection/Seq.html) has two subtraits [LinearSeq](http://www.scala-lang.org/api/current/scala/collection/LinearSeq.html), and [IndexedSeq](http://www.scala-lang.org/api/current/scala/collection/IndexedSeq.html). These do not add any new operations to the immutable branch, but each offers different performance characteristics: A linear sequence has efficient `head` and `tail` operations, whereas an indexed sequence has efficient `apply`, `length`, and (if mutable) `update` operations. Frequently used linear sequences are `scala.collection.immutable.List` and `scala.collection.immutable.LazyList`. Frequently used indexed sequences are `scala.Array` and `scala.collection.mutable.ArrayBuffer`. The `Vector` class provides an interesting compromise between indexed and linear access. It has both effectively constant time indexing overhead and constant time linear access overhead. Because of this, vectors are a good foundation for mixed access patterns where both indexed and linear accesses are used. You'll learn more on vectors [later](concrete-immutable-collection-classes.html).