[PATCH v3 0/3] contributor doc update around log messages

We already explain _how_ to write log messages, but did not tell readers why we care. Add a few paragraphs to SubmittingPatches and CodingGuidelines to do so.

Junio C Hamano (3):
  SubmittingPatches: write problem statement in the log in the present
    tense
  CodingGuidelines: hint why we value clearly written log messages
  SubmittingPatches: explain why we care about log messages

 Documentation/CodingGuidelines  |  7 +++++++
 Documentation/SubmittingPatches | 36 +++++++++++++++++++++++++++++++++
 2 files changed, 43 insertions(+)

Range-diff against v2:
-:  ---------- > 1:  b86a706bfd SubmittingPatches: write problem statement in the log in the present tense
1:  35e39deb7d ! 2:  a65df87939 CodingGuidelines: hint why we value clearly written log messages
    @@ Documentation/CodingGuidelines: code.  For Git in general, a few rough rules are
         go and fix it up."
         Cf. http://lkml.iu.edu/hypermail/linux/kernel/1001.3/01069.html
      
    -+ - Log messages to explain your changes are as much important as the
    ++ - Log messages to explain your changes are as important as the
     +   changes themselves.  Clearly written code and in-code comments
     +   explain how the code works and what is assumed from the surrounding
     +   context.  The log messages explain what the changes wanted to
2:  fb54bcfcda < -:  ---------- SubmittingPatches: explain why we care about log messages
-:  ---------- > 3:  77d918fb98 SubmittingPatches: explain why we care about log messages