warning output from the go api tool. Each file should be named
nnnnn.txt, after the issue number for the accepted proposal.
(The #nnnnn suffix must also appear at the end of each line in the file;
that will be preserved when next/*.txt is concatenated into go1.XX.txt.)

When you add a file to the api/next directory, you must add at least one file

corresponding to standard library package paths, and headings for those package
paths will be generated automatically.

Files in this repo's `api/next` directory must have corresponding files in
`doc/next/*stdlib/*minor`.
The files should be in the subdirectory for the package with the new
API, and should be named after the issue number of the API proposal.

The [SetCrashOutput] function allows the user to specify an alternate
file to which the runtime should write its fatal crash report.
It may be used to construct an automated reporting mechanism for all
unexpected crashes, not just those in goroutines that explicitly use