go-to-definition stops working without editing the file

[st0012]

This is caused by Shopify/ruby-lsp#2082 excluding the spec folder from the default indexing, which was what provides the definitions of subject and let declarations.
Without the initial indexing, we can only rely on individual files' indexing to add those definitions, which only happens when the file is edited.

The ideal solution is for Ruby LSP to introduce index-on-file-read as well. This issue is simply an acknowledgement to the problem.