[autocmd] Added autocmd group for markdown

Change-Id: If0ea214421db408e268589467fbe012238a4e250
[doc] Updated plugins list and added the main features infos

Added at the beginning the main features and additionally an updated list of
the installed plugins.

Change-Id: I68c682e64c3f9655f25e0134137eb6713e7ced4a
[doc] Fixed documentation foramtting

Change-Id: I31446064246745a98be22cfb8e75337f4d73ddc8