README: Tweak

Mention that Toolbx is meant for system administrators to troubleshoot
the host operating system.  The word 'debugging' is often used in the
context of software development, and hence most readers might not
interpret it as 'troubleshooting'.

containers#1182

README.md

@@ -18,12 +18,12 @@ This is particularly useful on
 systems is to discourage installation of software on the host, and instead
 install software as (or in) containers — they mostly don't even have package
 managers like DNF or YUM. This makes it difficult to set up a development
-environment or install tools for debugging in the usual way.
+environment or troubleshoot the operating system in the usual way.
 
 Toolbox solves this problem by providing a fully mutable container within
-which one can install their favourite development and debugging tools, editors
-and SDKs. For example, it's possible to do `yum install ansible` without
-affecting the base operating system.
+which one can install their favourite development and troubleshooting tools,
+editors and SDKs. For example, it's possible to do `yum install ansible`
+without affecting the base operating system.
 
 However, this tool doesn't *require* using an OSTree based system. It works
 equally well on Fedora Workstation and Server, and that's a useful way to