Fix ToggleTerm buffers to window & Propagate opened files to other windows

`:h winfixbuf`

I'm commonly facing the problem that I accidentally open a file or my file browser inside of a ToggleTerm buffer. To avoid this, one can simply `:set winfixbuf`, which imo should be the default for this plugin at least.

Ideally, when opening a file path under the cursor with `gf`, the file should be opened in another window which isn't a ToggleTerm one.

What do you think?