docs: Clarify GOOGLE_BUILDABLE meaning

This was from feedback in https://stackoverflow.com/questions/78293590

Author: jskeet

docs/deployment.md

@@ -134,9 +134,12 @@ from that top-level directory instead of from the function's project
 directory. You also need to use the `--set-build-env-vars` command
 line flag to specify the `GOOGLE_BUILDABLE` build-time environment
 variable. This tells the Google Cloud Functions deployment process
-which project to build and deploy. Note that the `GOOGLE_BUILDABLE`
-environment variable value is case-sensitive, and should match the
-directory and file names used.
+the path to the project to build and deploy. Note that the
+`GOOGLE_BUILDABLE` environment variable value is case-sensitive,
+and should match the directory and file names used. Additionally,
+note that the value is the path to the project, *not* a .NET assembly
+name or namespace. (In many cases these will be the same, but not
+always.)
 
 When deploying a function with multiple projects, it's important to
 make sure you have a suitable

docs/examples.md

@@ -474,7 +474,9 @@ This uses the [.gcloudignore
 file in the examples directory](../examples/.gcloudignore) to avoid uploading already-built
 binaries.
 
-Note that the ability to set build environment variables is currently in beta.
+Note that the `GOOGLE_BUILDABLE` value is a path to the relevant
+project; in this case it just happens to be the name of the resulting
+assembly.
 
 ## LocalNuGetPackageFunction and LocalNuGetPackageCode