- Remove unnecessary checks for `ctx.Repo.TreePath`, because it will
already early-return if it's empty.
- Simplify `performBlame` to extract the repoPath from the context.
- Don't render the topics, as they are not shown in the blame
page (there's a condition in the template for the blame page).
- Fix that `performBlame` doesn't call `NotFound`, it should instead
only return the error.
- Fix that the error handlings call `ServerError` instead of `NotFound`.
- Simplify `bypass-blame-ignore` to use `ctx.FormBool`.
- Remove `TreeLink`, `HasParentPath` and `ParentPath` as it's not used
in the blame template.
- Inline `BranchLink` and `RawFileLink` string operations.
- Move around `NumLines` to make it clear the error is handled.
- Less code, less things the code does, more readable and thus more
maintanable!
(cherry picked from commit e02baca55c0a3ed6a806f276c8e3cf2995a88967)
(cherry picked from commit 74e00620ca4de9a2aaa51f30fdf8136b581c7a21)