fix: buffer not in list when go to references

[nfwyst]

Description

there is file opened but is nobuflisted when go to references with no jump_type, so create a buffer before setting win buf is good

Type of change

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce. Please also list relevant details about your configuration

• Test go to references with jump_type nil, open file in buffer, then call command :buffers should see it

Configuration:

• Neovim version (nvim --version): 0.9.2
• Operating system and version: darwin arm64, 13.6 (22G120)

Checklist:

• My code follows the style guidelines of this project (stylua)
• I have performed a self-review of my own code