Change starting slot for treeview position from 0 to 1

[julianmichael]

Fixes #14.

I changed the constant to 1 here at both callsites but could also just add 1 to it in the lsp-metals-treeview--show-views function instead.

This also does change the behavior from replacing the file tree buffer (which I guess is slot 0 by default) to opening a new window under it. I feel like this is a positive (and hopefully uncontroversial) change, but can imagine why it might be something a user would want to configure.

[julianmichael]

Side comment: Even after this change, it seems to resize the lsp-metals treeview to take up half of the treeview window. I would prefer if it didn't change the size of the window so I could keep it shrunk down so it doesn't cover half of the file tree since the compilation progress only takes a max of a few lines anyway. Any ideas on how to do this?

[kurnevsky]

I'm going to close this due to discussion in the issue.