Bug#794778: Should update to gcc-5-doc packages

[Yuri D'Elia <wavexx@thregr.org>]

Package: gcc-doc
Version: 5:4.9.2-1
Severity: normal

Now that gcc 5 is the new default, gcc-doc/cpp-doc/etc should depend on the
newer 5 versions.

Thanks.

-- System Information:
Debian Release: stretch/sid
  APT prefers unstable
  APT policy: (900, 'unstable'), (800, 'experimental')
Architecture: amd64 (x86_64)

Kernel: Linux 4.0.0-2-amd64 (SMP w/4 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages gcc-doc depends on:
ii  gcc-4.9-doc  4.9.2-2

gcc-doc recommends no packages.

gcc-doc suggests no packages.