Switch environment precedence, or offer another option?
I'm trying to make a user guide that links to the rust documentation, and I want to be able to link to local documentation by default, but in CI, override the base URL to the desired location when publishing the book.
With the current use_env
precedence, I cannot specify a default value in book.toml, because it will prevent the environment variable from ever being read.
Rather than write my own preprocessor with inverse semantics, I wanted to check if you would accept a PR that switched the precedence to prefer environment variables over toml or potentially to add a new option to allow configuring the precedence.