Fixed date to move to ddox for Phobos documentation

[Vladimir Panteleev via Digitalmars-d]

On Saturday, 4 June 2016 at 16:10:14 UTC, Seb wrote:
> Imho it's quite impressive that he still pushes the project and 
> as Adam
> correctly said - we need to make a decision and have a clear 
> deadline like 2.072 will be the last documentation build with 
> ddoc, once it's released we will remove the ddoc Phobos build 
> and make ddox (/library) the standard (with redirect, of 
> course). This gives us also two to three months to test it 
> properly again (it has been tested now for 2.5 years!!) and 
> resolve issues if occurring.

One wholesome switch is probably too harsh. We might discover new 
issues only after the switch. Instead it could be done gradually, 
in this order:

1. /library/ is promoted as the primary Phobos documentation in 
the site navigation.
2. /phobos/ is removed from search indexing.
3. /phobos/ is removed from site navigation.
4. /phobos/ is removed.

We could start with step 1 upon 2.072's release.