Fix minor typos (hmemcpy#304)

* typo (date -> data)

* Replace double colon with LaTeX \Colon

* typo (\eta_aa -> \eta_a)

* Replace \emph{} with \cat{}

* Add missing colon

* typo (× -> \times)

* typo (C -> $\cat{C}$)

* fixup! 38f8fe8e41038b2fab7fa068a78cff4fd2676e7438f8fe8e41038b2fab7fa068a78cff4fd2676e74

fix trivial typo in scala snippet (hmemcpy#303)

Revert wrong "typo fix" for "iff" (hmemcpy#298)

- 'iff' normally means 'if and only if', which is stronger than just 'if'.
https://en.wikipedia.org/wiki/If_and_only_if
- See the discussion on hmemcpy#294

Replace Greek letters with LaTeX (hmemcpy#294)

* Replace Greek letters with LaTeX

* Fix typo

Add missing comma (hmemcpy#280)

Add missing figure (hmemcpy#290) (hmemcpy#291)

Updated README.md as per issue hmemcpy#288 (hmemcpy#289)

* Updated README.md as per issue hmemcpy#288

* Added steps to install nixFlakes explicitly, ref hmemcpy#289

Improvements in the Nix and build system. (hmemcpy#287)

Use Nix for building PDFs. (hmemcpy#286)

Fix formatting in OCaml snippets (hmemcpy#279)