Code quality improvements (#677)

* Code quality improvements such -

1. Improves empty string test (len vs str == "")
2. Converts fmt.Sprintf to string literal and Printf to Print where possible (as the dynamic args are missing!)

* Delete .deepsource.toml

Co-authored-by: DeepSource Bot <bot@deepsource.io>
Co-authored-by: Liz Rice <liz@lizrice.com>