- Add the experimental
[deacode](https://pkg.go.dev/golang.org/x/tools/internal/cmd/deadcode)
linter to Forgejo.
- To deal with false positives that can happen due to build tags or with code
that's currently only referenced by test code, the output of the tool is
compared against a known-good output.
- This commit doesn't make any attempt to remove any deadcode.
(cherry picked from commit ac462279e9)
(cherry picked from commit b5ea6e85ac)
(cherry picked from commit 5915f3643c)
[CLEANUP] Remove deadcode
- This is deadcode since https://codeberg.org/forgejo/forgejo/pulls/1802
removed the usage of it.
(cherry picked from commit d840b9923e)
