Describe, how to adapt shell command output width in Tramp

* doc/misc/tramp.texi (Quick Start Guide, GVFS based methods):
Fix @cindex.
(Remote processes): Add some @vindex.  Describe shell command
output width.
1 job for master in 90 minutes and 1 second (queued for 2 seconds)
Status Job ID Name Coverage
  Test
failed #1663
test-all

01:30:01

 
Name Stage Failure
failed
test-all Test The script exceeded the maximum execution time set for the job
  GEN      lisp/eshell/eshell-tests.log
ELC lisp/faces-tests.elc
GEN lisp/faces-tests.log
ELC lisp/ffap-tests.elc
GEN lisp/ffap-tests.log
ELC lisp/filenotify-tests.elc
GEN lisp/filenotify-tests.log
Pulling docker image gitlab/gitlab-runner-helper:x86_64-f100a208 ...
ERROR: Job failed: execution took longer than 1h30m0s seconds