add comment, readme notes

Author: mortenpi

README.md

@@ -84,3 +84,7 @@ Check [`.github/workflows/deploy.yml`](.github/workflows/deploy.yml) and [`docs/
 The result of that script is available at [https://juliacomputing.github.io/MultiDocumenter.jl/](https://juliacomputing.github.io/MultiDocumenter.jl/).
 
 You can of course also just push the output artefact directly to S3 or some other hosting service.
+
+> **Warning**
+> MultiDocumenter sites can not be deployed on Windows right now.
+> See [#70](https://github.com/JuliaComputing/MultiDocumenter.jl/issues/70).

test/runtests.jl

@@ -85,7 +85,10 @@ docs = [
     ),
 ]
 
-if Sys.iswindows()
+# We do not support deploying docs on Windows at the moment, and MultiDocumenter
+# should throw an error if it's being run on Windows (in a non-interactive session).
+# See also: https://github.com/JuliaComputing/MultiDocumenter.jl/issues/70
+if Sys.iswindows() && !isinteractive()
     @test_throws ErrorException MultiDocumenter.make(
         outpath,
         docs;