This changes the packageErrorSpan function into the listErrorSpan.
Previously, this was causing the gopls-generated errors to get parsed,
which would result in attempts to send diagnostics for invalid filenames.
Fixesgolang/go#32603
Change-Id: I7a54ed8884b78beb3f894598f18a24ed232f7412
Reviewed-on: https://go-review.googlesource.com/c/tools/+/182460
Run-TryBot: Rebecca Stambler <rstambler@golang.org>
Reviewed-by: Ian Cottrell <iancottrell@google.com>