minor readme update

Author: jnsiemer

README.md

@@ -90,7 +90,7 @@ See [Contributing](https://github.com/qfall/math/blob/dev/CONTRIBUTING.md) for d
 
 Please use the following bibtex entry to cite [qFALL](https://qfall.github.io).
 
-```text
+```bibtex
 @misc{qfall,
       author = {Marvin Beckmann and Phil Milewski and Laurens Porzenheim and Marcel Luca Schmidt and Jan Niklas Siemer},
       title = {{qFALL} – Rapid Prototyping of Lattice-based Cryptography},