Update _episodes/06-debugging.md

Co-authored-by: Peter Kalverla <[email protected]>

Author: SarahAlidoost

_episodes/06-debugging.md

@@ -16,7 +16,7 @@ The good news is, ``ESMValTool`` creates a record of the output messages and sto
 They can be used for debugging or monitoring the process.
 This lesson helps to understand what the different types of errors are and when you are likely to encounter them.
 
-## log files
+## Log files
 
 Each time we run the ESMValTool, it will produce a new output directory.
 This directory should contain the ``run`` folder that is automatically generated by ESMValTool.