[binutils-gdb] Update help text for "jump" command

[sergiodj+buildbot@sergiodj.net]

*** TEST RESULTS FOR COMMIT 0a8ba311d0c4facef158af3d79c78489d5efcc4b ***

Author: Tom Tromey <tom@tromey.com>
Branch: master
Commit: 0a8ba311d0c4facef158af3d79c78489d5efcc4b

Update help text for "jump" command

This updates the usage text for the "jump" command to conform to the
GNU style.

2018-04-29  Tom Tromey  <tom@tromey.com>

	* infcmd.c (_initialize_infcmd): Update help text.