Add pull request links

Author: Atry

_sips/sips/2018-08-20-converters-among-optional-functions-partialfunctions-and-extractor-objects.md

@@ -72,7 +72,9 @@ val csvRow: String => Option[Seq[String]] = { line =>
 
 ## Implementation
 
-The `extract` method has been implemented in a library: [Extractor.scala](https://github.com/ThoughtWorksInc/Extractor.scala), which has been used in Binding.scala in order to [extract patterns of XML literals](https://github.com/ThoughtWorksInc/Binding.scala/blob/10.0.x/XmlExtractor/src/main/scala/com/thoughtworks/binding/XmlExtractor.scala#L63).
+The `extract` method was originally implemented in a library: [Extractor.scala](https://github.com/ThoughtWorksInc/Extractor.scala), which has been used in Binding.scala in order to [extract patterns of XML literals](https://github.com/ThoughtWorksInc/Binding.scala/blob/10.0.x/XmlExtractor/src/main/scala/com/thoughtworks/binding/XmlExtractor.scala#L63).
+
+The new implementation aims to become part of core library. The pull request can be found at [#7111][2].
 
 ## Drawbacks
 
@@ -82,5 +84,7 @@ process anyway so it's better to get them out up front.
 ## References
 
 1. [Existing Implementation (Extractor.scala)][1]
+2. [Related Pull Request][2]
 
 [1]: https://github.com/ThoughtWorksInc/Extractor.scala "Extractor.scala"
+[2]: https://github.com/scala/scala/pull/7111 "#7111"