Fix borked links (#2119)

Author: marxin

src/appendix/background.md

@@ -329,5 +329,5 @@ does not.
 - [nLab](https://ncatlab.org/nlab/show/HomePage)
 
 ## Misc Papers and Blog Posts
-- [Programming in Martin-Löf's Type Theory](https://www.researchgate.net/publication/213877272_Programming_in_Martin-Lof's_Type_Theory)
+- [Programming in Martin-Löf's Type Theory](https://www.cse.chalmers.se/research/group/logic/book/)
 - [Polymorphism, Subtyping, and Type Inference in MLsub](https://dl.acm.org/doi/10.1145/3093333.3009882)

src/appendix/bibliography.md

@@ -28,7 +28,7 @@ Rust, as well as publications about Rust.
 * [Language support for fast and reliable message passing in singularity OS](https://research.microsoft.com/pubs/67482/singsharp.pdf)
 * [Non-blocking steal-half work queues](https://www.cs.bgu.ac.il/%7Ehendlerd/papers/p280-hendler.pdf)
 * [Reagents: expressing and composing fine-grained concurrency](https://aturon.github.io/academic/reagents.pdf)
-* [Scheduling multithreaded computations by work stealing](http://supertech.csail.mit.edu/papers/steal.pdf)
+* [Scheduling multithreaded computations by work stealing](https://www.lri.fr/~cecile/ENSEIGNEMENT/IPAR/Exposes/cilk1.pdf)
 * [Scheduling techniques for concurrent systems](https://www.stanford.edu/~ouster/cgi-bin/papers/coscheduling.pdf)
 * [Singularity: rethinking the software stack](https://research.microsoft.com/pubs/69431/osr2007_rethinkingsoftwarestack.pdf)
 * [The data locality of work stealing](http://www.aladdin.cs.cmu.edu/papers/pdfs/y2000/locality_spaa00.pdf)

src/appendix/humorust.md

@@ -4,7 +4,7 @@ What's a project without a sense of humor? And frankly some of these are
 enlightening?
 
 - [Weird exprs test](https://github.com/rust-lang/rust/blob/master/tests/ui/weird-exprs.rs)
-- [Ferris Rap](http://fitzgeraldnick.com/2018/12/13/rust-raps.html)
+- [Ferris Rap](https://fitzgen.com/2018/12/13/rust-raps.html)
 - [The Genesis of Generic Germination](https://github.com/rust-lang/rust/pull/53645#issue-210543221)
 - [The Bastion of the Turbofish test](https://github.com/rust-lang/rust/blob/79d8a0fcefa5134db2a94739b1d18daa01fc6e9f/src/test/ui/bastion-of-the-turbofish.rs)
 - [Rust Koans](https://users.rust-lang.org/t/rust-koans/2408)