Review

- Corrected typos (missing colons, spacing, capital letter)
- Uppercase acronyms (s/html/HTML/, s/xml/XML/)
- Styling (s/extension xml/extension `.xml`/)
Merge pull request #78 from eguaj/relecture_representations

Relecture "Vues et représentations", chap. 6.{1,2,3,4,5}