10. migration doc flaw

[Rob Sargent]

I think there's an error on this page:

   http://tomcat.apache.org/migration-10.html

First paragraph under "Upgrading 10.0.x"

   When upgrading instances of Apache Tomcat from one version of
   _Tomcat 9 _to another, particularly when using separate

Which confused me because I was looking for 9.0 to 10.0 instrux, but 
this isn't the page for that, I don't think.