Fix linter

Author: uekerman

05_testing_and_ci/boost_testing_sidemade_demo.md

@@ -50,7 +50,7 @@ Repository: [testing boost exercise – demo-start branch](https://github.com/Si
     target_link_libraries(testsidemade PRIVATE Boost::unit_test_framework)
     add_test(NAME "MatrixSolverTests" COMMAND ${CMAKE_CURRENT_BINARY_DIR}/testsidemade)
     ```
-    
+
     - `add_test` can work with anything that returns an exit code. Does not have to be a fancy testing framework.
 
 - Reconfigure CMake, build, run via ...