Clarifying placing rules

Readme.md

@@ -75,4 +75,5 @@ When adding a new analyzer package, do the following:
 - Go through all rules in the package and decide one by one whether we need them.
   - Check for rules that are already covered by some other analyzer and disable duplicates.
   - All rules that we need should be surfaced as Warnings. This allows to only break the build on analyzer violations when we need it, i.e. during CI builds but not during development.
+  - Add rule configuration to the _.globalconfig_ file of the relevant project, depending on which kind of applications they're applicable to. Editor-only configuration should be in _.editorconfig_ files.
 - Test it on multiple significant solutions. Using the [Hastlayer SDK](https://github.com/Lombiq/Hastlayer-SDK) is a good example as it's a large C# solution.