doc: add vty command information about brief usage

[pguibert6WIND]

brief keyword can be used along with vrf NAME or vrf all.

Signed-off-by: Philippe Guibert philippe.guibert@6wind.com

[LabN-CI]

💚 Basic BGPD CI results: SUCCESS, 0 tests failed

Results table

_	_
Result	SUCCESS git merge/5081 fbe49ed
Date	09/30/2019
Start	04:07:23
Finish	04:29:03
Run-Time	21:40
Total	1815
Pass	1815
Fail	0
Valgrind-Errors	0
Valgrind-Loss	0
Details	vncregress-2019-09-30-04:07:23.txt
Log	autoscript-2019-09-30-04:08:13.log.bz2
Memory	436 432 360

For details, please contact louberger

[NetDEF-CI]

Continuous Integration Result: SUCCESSFUL

Congratulations, this patch passed basic tests

Tested-by: NetDEF / OpenSourceRouting.org CI System

CI System Testrun URL: https://ci1.netdef.org/browse/FRR-FRRPULLREQ-9079/

This is a comment from an automated CI system.
For questions and feedback in regards to this CI system, please feel free to email
Martin Winter - mwinter (at) opensourcerouting.org.

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CLANG Static Analyzer Summary

• Github Pull Request 5081, comparing to Git base SHA 5c256b5

No Changes in Static Analysis warnings compared to base

1 Static Analyzer issues remaining.

See details at
https://ci1.netdef.org/browse/FRR-FRRPULLREQ-9079/artifact/shared/static_analysis/index.html