Remove broken links

Fixes #1198

readme.md

@@ -539,7 +539,6 @@
 - [first-chunk-stream](https://github.com/sindresorhus/first-chunk-stream) - Transform the first chunk in a stream.
 - [pad-stream](https://github.com/sindresorhus/pad-stream) - Pad each line in a stream.
 - [multistream](https://github.com/feross/multistream) - Combine multiple streams into a single stream.
-- [stream-combiner2](https://github.com/substack/stream-combiner2) - Turn a pipeline into a single stream.
 - [readable-stream](https://github.com/nodejs/readable-stream) - Mirror of Streams2 and Streams3 implementations in core.
 - [through2-concurrent](https://github.com/almost/through2-concurrent) - Transform object streams concurrently.
 
@@ -920,7 +919,6 @@
 - [Node.js Best Practices](https://github.com/goldbergyoni/nodebestpractices) - Summary and curation of the top-ranked content on Node.js best practices, available in multiple languages.
 - [Nodeschool](https://github.com/nodeschool) - Learn Node.js with interactive lessons.
 - [The Art of Node](https://github.com/maxogden/art-of-node/#the-art-of-node) - An introduction to Node.js.
-- [stream-handbook](https://github.com/substack/stream-handbook) - How to write Node.js programs with streams.
 - [module-best-practices](https://github.com/mattdesl/module-best-practices) - Some good practices when writing new npm modules.
 - [The Node Way](https://thenodeway.io) - An entire philosophy of Node.js best practices and guiding principles exists for writing maintainable modules, scalable applications, and code that is actually pleasant to read.
 - [You Don't Know Node.js](https://github.com/azat-co/you-dont-know-node) - Introduction to Node.js core features and asynchronous JavaScript.