Invalid workspaceFolders breaks gopls

Hi, Qt Creator doesn't work with the Go language server (gopls), started in per-project mode. gopls dies with the following message and a stacktrace:

panic: only file URIs are supported, got "" from "/home/user/foo"

Just looking at the debugging output, two things appear to be off:

{{{{"workSpaceFolders":[

]}}}}

First, "workSpaceFolders" should probably be "workspaceFolders", see https://microsoft.github.io/language-server-protocol/specification.html although it doesn't seem to be the cause of this failure.

Second, the URI is not a URI and should be prefixed by file://, giving:

{{{{"workspaceFolders":[

]}}}}

The latter should be an easy and straight-forward fix. Thanks.

Note that there are more problems with gopls, this is just the first one I bothered to investigate.