[fr] Update chapter on diffing
[fr] sync with 90c92ceb
[fr] sync with 21e84add
[fr] sync with 2a0a8371
[fr] apply 15f2bf1b
[fr] apply bdef6f76 and 1ca5ef16
fix  chap 4.
[fr] update with bdef6f76
[fr] sync with c418e2ea
[fr] Sync with ceba7dfb
[fr] Sync with 60e26189
Merge pull request #819 from progit/resync_fr

Resync fr