proxmox-backup-client: add explanatory comments to patches

  sourceRoot = "proxmox-backup";

  # These patches are essentially un-upstreamable, due to being "workarounds" related to the

  # project structure.

  cargoPatches = [

    # A lot of Rust crates `proxmox-backup-client` depends on are only available through git (or

    # Debian packages). This patch redirects all these dependencies to a local, relative path, which

    # works in combination with the other three repos being checked out.

    (fetchpatch {

      name = "0001-re-route-dependencies-not-available-on-crates.io-to-.patch";

      url = "https://aur.archlinux.org/cgit/aur.git/plain/0001-re-route-dependencies-not-available-on-crates.io-to-.patch?h=proxmox-backup-client&id=83a1f4dfcb04bd181b11954b1d9f5ddfcb72b3d0";

      hash = "sha256-2YZtjbpYSbRk6rmpjKJeIO+V0YN5PrKsISONXMj4RG0=";

    })

    # This patch prevents the generation of the man-pages for other components inside the repo,

    # which would require them too be built too. Thus avoid wasting resources and just skip them.

    (fetchpatch {

      name = "0002-docs-drop-all-but-client-man-pages.patch";

      url = "https://aur.archlinux.org/cgit/aur.git/plain/0002-docs-drop-all-but-client-man-pages.patch?h=proxmox-backup-client&id=83a1f4dfcb04bd181b11954b1d9f5ddfcb72b3d0";

      hash = "sha256-oJKQs4SwJvX5Zd0/l/vVr66aPO7Y4AC8byJHg9t1IhY=";

    })

    # `make docs` assumes that the binaries are located under `target/{debug,release}`, but due

    # to how `buildRustPackage` works, they get put under `target/$RUSTC_TARGET/{debug,release}`.

    # This patch simply fixes that up.

    ./0001-docs-Add-target-path-fixup-variable.patch

  ];