Support indecrement to date, datetime

[nishigori]

Q	A
Bug fix?	no
New feature?	yes
BC breaks?	no?
Deprecations?	no

When exec increment auto detecting for date

Case examples)

• 2013-03-31 <-> 2013-04-01
• 2010/12/31 <-> 2011/01/01
• 2036-02-28 <-> 2036-02-29

[Freed-Wu]

Can this feature support? or can it work with https://github.com/tpope/vim-speeddating? thanks!

[nishigori]

@Freed-Wu Thanks for the useful information!
I'll try to call vim-speeddating internally.