Update paper links and instructions in README.

Author: yegor256

README.md

@@ -1,14 +1,14 @@
-<img src="https://www.objectionary.com/cactus.svg" height="100px"/>
+# LaTeX Sources of the "Reducing Programs to Objects" Paper
 
 [![arXiv](https://img.shields.io/badge/arXiv-2112.11988-green.svg)](https://arxiv.org/abs/2112.11988)
 [![make](https://github.com/yegor256/reducing-programs-to-objects/actions/workflows/latexmk.yml/badge.svg)](https://github.com/yegor256/reducing-programs-to-objects/actions/workflows/latexmk.yml)
 
-The paper is published [in arXiv](https://arxiv.org/abs/2112.11988) (draft is [here](https://github.com/objectionary/reducing-programs-to-objects/blob/gh-pages/paper.pdf)).
+The paper is published in [arXiv] (draft is in this [PDF]).
 
 To build it, just run:
 
 ```bash
-$ make
+make
 ```
 
 You need to have
@@ -20,4 +20,7 @@ and
 [`texqc`](https://rubygems.org/gems/texqc)
 installed.
 
-Once compiled and packaged, upload zip archive to [arXiv](https://arxiv.org/abs/2112.11988).
+Once compiled and packaged, upload zip archive to [arXiv].
+
+[PDF]: https://github.com/objectionary/reducing-programs-to-objects/blob/gh-pages/paper.pdf
+[arXiv]: https://arxiv.org/abs/2112.11988