feat: dedup and sort oma rdepends output

[stdmnpkg]

oma rdepends will print an entry for every version of a package, cause many seemingly duplicated entries.

this PR mitigated above effect by dedup these entries.

before & after:

studentmain@MeowPC3E [ oma@rdepends-output-dedup ] $ oma rdepends kio-fuse
kio-fuse:
  Reverse dependencies:
    Depends: kio-fuse-dbg (kio-fuse = 5.0.1-2)
    Depends: xdg-desktop-portal-kde (kio-fuse >= 5.0.1-2)
    Depends: xdg-desktop-portal-kde (kio-fuse >= 5.0.1-2)
    Depends: xdg-desktop-portal-kde (kio-fuse >= 5.0.1-2)
    Depends: xdg-desktop-portal-kde (kio-fuse >= 5.0.1-2)
    Depends: xdg-desktop-portal-kde (kio-fuse >= 5.0.1-2)
    Depends: xdg-desktop-portal-kde (kio-fuse >= 5.0.1-2)
    Depends: xdg-desktop-portal-kde (kio-fuse >= 5.0.1-2)
    Depends: xdg-desktop-portal-kde (kio-fuse >= 5.0.1-2)
    Depends: xdg-desktop-portal-kde (kio-fuse >= 5.0.1-2)
    Depends: xdg-desktop-portal-kde (kio-fuse >= 5.0.1-2)
    Depends: xdg-desktop-portal-kde (kio-fuse >= 5.0.1-2)
    Depends: xdg-desktop-portal-kde (kio-fuse >= 5.0.1-2)
    Depends: xdg-desktop-portal-kde (kio-fuse >= 5.0.1-2)
    Depends: plasma-workspace (kio-fuse >= 5.0.1-2)
    Depends: plasma-workspace (kio-fuse >= 5.0.1-2)
    Depends: plasma-workspace (kio-fuse >= 5.0.1-2)
    Depends: plasma-workspace (kio-fuse >= 5.0.1-2)
    Depends: plasma-workspace (kio-fuse >= 5.0.1-2)
    Depends: plasma-workspace (kio-fuse >= 5.0.1-2)
    Depends: plasma-workspace (kio-fuse >= 5.0.1-2)
    Depends: plasma-workspace (kio-fuse >= 5.0.1-2)
    Depends: plasma-workspace (kio-fuse >= 5.0.1-2)
    Depends: plasma-workspace (kio-fuse >= 5.0.1-2)
    Depends: plasma-workspace (kio-fuse >= 5.0.1-2)
    Depends: plasma-workspace (kio-fuse >= 5.0.1-2)
    Depends: plasma-workspace (kio-fuse >= 5.0.1-2)
    Depends: plasma-workspace (kio-fuse >= 5.0.1-2)
    Depends: plasma-workspace (kio-fuse >= 5.0.1-2)
    Depends: plasma-workspace (kio-fuse >= 5.0.1-2)
    Depends: plasma-workspace (kio-fuse >= 5.0.1-2)
    Depends: plasma-workspace (kio-fuse >= 5.0.1-2)
    Depends: xdg-desktop-portal-kde (kio-fuse >= 5.0.1-2)
    Depends: plasma-workspace (kio-fuse >= 5.0.1-2)
    Depends: plasma-workspace (kio-fuse >= 5.0.1-2)
studentmain@MeowPC3E [ oma@rdepends-output-dedup ] $ ./target/debug/oma rdepends kio-fuse
kio-fuse:
  Reverse dependencies:
    Depends: kio-fuse-dbg (kio-fuse = 5.0.1-2)
    Depends: plasma-workspace (kio-fuse >= 5.0.1-2)
    Depends: xdg-desktop-portal-kde (kio-fuse >= 5.0.1-2)
studentmain@MeowPC3E [ oma@rdepends-output-dedup ] $ 

alternative solution is show source package's version info, so it's no longer duplicate.

e.g.

pkg1:
  Reverse dependencies:
    Depends: pkg2 1.0 (pkg1 >= 1)
    Depends: pkg2 1.1 (pkg1 >= 1)

[eatradish]

This modification is not correct, the duplication is due to different versions of this package being output and duplicated. oma depends/rdepends mimics the output of apt , and I don't have any ideas for improving it at the moment.