logcat: Adjust help to make it more meaningful

(cherry pick from commit 378f4745a27632f3bb26e7029fe55142001f3d47)

It is not clear about the long option aliases, list
them comma separate first for clarity. Squash lines
of help content if possible. Lock to 3 indents, one
for options, another for text on same line as options
and another for next line or continuation.

Bug: 28120456
Bug: 28788401
Bug: 28813587
Change-Id: I5331acde3ac0fd3b87f6699ba108f6cef46a1563
1 file changed