Failure when asked to give definition in file that wasn't explicitly opened

[PMunch]

In Vim when I run :LspDefinition in my own project it works fine and opens the file where the definition resides. However this file isn't explicitly opened by a textDocument/didOpen event, so trying to follow a definition further into this file will fail as the key is not found in projectFiles. Whether this is a bug in NimLSP or VimLSP is currently unknown (any input on this is much appreciated), but a fallback should probably be added in NimLSP either way to automatically open non-opened files.