patch-detail: left align message headers

patch-detail: left align message headers

Change both of the message containers in the "Commit Message" and
"Comments" to have their content be left-aligned which improves the
proximity of items which boosts the efficiency of gathering information
and performing actions. Before [1] and after [2] images for reference.

[1] https://i.imgur.com/ji2ZINL.png
[2] https://i.imgur.com/Dtn8lm9.png

Signed-off-by: Raxel Gutierrez <raxel@google.com>
Reviewed-by: Stephen Finucane <stephen@that.guru>
Signed-off-by: Daniel Axtens <dja@axtens.net>