Update lsp_show_scope_name command for ST 4127

[jwortmann]

It looks like the View.context_backtrace() API function had a backward incompatible change on ST 4127, so I guess the scope name popup from LSP is broken for new ST versions now. This only impacts active language servers which support semantic tokens, and only if the "semantic_highlighting" setting is enabled.

A solution would be to add something like if sublime.version() > "4126" and copy the relevant new code from Default/show_scope_name.py into this if-branch. Or probably even better would be to add a new tag at https://github.com/sublimelsp/repository/blob/ccc25996a2ee05d70457344219a6dd62130ad2ac/repository.json#L59-L68 for the LSP package. The current version of LSP does no longer work on ST 4070 anyway.