Readme.md aesthetics: put PowSyBl in bold

Author: jonenst

Diff for: README.md

@@ -6,7 +6,7 @@
 [![MPL-2.0 License](https://img.shields.io/badge/license-MPL_2.0-blue.svg)](https://www.mozilla.org/en-US/MPL/2.0/)
 [![Javadocs](https://www.javadoc.io/badge/com.powsybl/powsybl-gse.svg?color=blue)](https://www.javadoc.io/doc/com.powsybl/powsybl-gse)
 
-PowSyBl (Power System Blocks) is an open source framework written in Java, that makes it easy to write complex software for power systems’ simulations and analysis. Its modular approach allows developers to extend or customize its features.
+PowSyBl (**Pow**er **Sy**stem **Bl**ocks) is an open source framework written in Java, that makes it easy to write complex software for power systems’ simulations and analysis. Its modular approach allows developers to extend or customize its features.
 
 PowSyBl is part of the LF Energy Foundation, a project of The Linux Foundation that supports open source innovation projects within the energy and electricity sectors.