Noteable additions:
- `redefines-builtin-id` forbid variable names that shadow go builtins
- `empty-lines` remove unnecessary empty lines that `gofumpt` does not
remove for some reason
- `superfluous-else` eliminate more superfluous `else` branches
Rules are also sorted alphabetically and I cleaned up various parts of
`.golangci.yml`.
(cherry picked from commit 74f0c84fa4245a20ce6fb87dac1faf2aeeded2a2)
Conflicts:
.golangci.yml
apply the linter recommendations to Forgejo code as well
