Fixed Wrong Naming of WSL (#208)

Fixed wrong naming of WSL.

README.md

@@ -34,7 +34,7 @@ using PETSc
 PETSc.libs
 ```
 ## Windows users 
-The package currently does not work on windows, mainly because `MicrosoftMPI_jll` does not function when used along with the precompiled version used in `PETSc_jll`. Windows users are therefore advised to install the Windows Subshell for Linux (WSL) and run PETSc through there. 
+The package currently does not work on windows, mainly because `MicrosoftMPI_jll` does not function when used along with the precompiled version used in `PETSc_jll`. Windows users are therefore advised to install the [Windows Subsystem for Linux](https://en.wikipedia.org/wiki/Windows_Subsystem_for_Linux) (WSL) and run PETSc through there. 
 
 ## Getting started
 The documentation is currently rather minimalistic; yet, if you want to see what is possible have a look at the [examples](./examples/) directory or at the tests in the [test](./test) directory. We do keep the tests up to date, so that is a good starting point.