gitk: Indent word-wrapped lines in commit display header
gitk: Indent word-wrapped lines in commit display header

In the cases where the lines starting with Precedes:, Follows: and
Branches: in the commit display are long enough to be word-wrapped,
this adds a 1cm margin on the left of the wrapped lines, to make
the display more readable.  Suggested by Stephen Rothwell.

Signed-off-by: Paul Mackerras <19a0ba370c443ba08d20b5061586430ab449ee8c@samba.org>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git