Support clients without workspaces

[jgarte]

Hi, my editor is vis and the lsp implementation that is available doesn't support workspaces.

It currently works with clangd but I'd like to use ccls.

How much work would it be to support clients without workspaces like clangd does?

Is this within the project scope?

See this issue.

System information

• ccls version (git describe --tags --long): 0.20210330
• clang version: 3.9.1
• OS: void linux
• Editor: vis