[elpa] externals/denote updated (2ab74c1d47 -> c6bc62d6c9)

[ELPA Syncer]

elpasync pushed a change to branch externals/denote.

      from  2ab74c1d47 Merge pull request #495 from 
jeanphilippegg/denote--date-convert
       new  05edc7dc5e Make it possible to rewrite the front matter even if 
file name is unchanged
       new  ee8b53b5c9 Use denote-file-has-denoted-filename-p in fontification
       new  119624e038 Small refactor of denote-directory-files
       new  edda750506 Handle nil date in front matter date functions
       new  3ca5797934 Add denote-file-is-in-denote-directory-p
       new  5541eebbb9 Use denote-file-has-supported-extension-p instead of 
denote-filename-is-note-p
       new  f11966e642 Add check in denote--get-all-used-ids
       new  f6fe1e27e6 Merge pull request #497 from jeanphilippegg/some-changes
       new  2f1a221f5d Define the markdown-obsidian front matter in 
denote-md-extras.el
       new  af8279fba4 Merge branch 'obsidian-file-type'
       new  c6bc62d6c9 Document the optional use of Obsidian-style front matter


Summary of changes:
 README.org          | 23 ++++++++++++++-
 denote-md-extras.el | 15 ++++++++++
 denote.el           | 82 ++++++++++++++++++++++++++++++-----------------------
 3 files changed, 83 insertions(+), 37 deletions(-)