Add a resources chapter

Author: ehuss

reference-dev-guide/src/SUMMARY.md

@@ -21,4 +21,4 @@
     - [Language and grammar]()
     - [Punctuation](style/punctuation.md)
 - [Review policy](review-policy.md)
-- [Resources]()
+- [Resources](resources.md)

reference-dev-guide/src/resources.md

@@ -0,0 +1,6 @@
+# Resources
+
+The Reference team has collected a set of resources about language specifications and technical writing.
+
+- [Language specs](https://hackmd.io/@rust-spec-team/HJey-puL6) --- It can be very useful to become familiar with how other languages are specified. This includes papers, standards, and commentary on how languages are specified.
+- [Style and writing guides](https://hackmd.io/@rust-spec-team/rkj1RS3uR) --- This contains a large list of different English and technical writing guides.