fix std/range/constraints.d static errors

remove scope import in std.range.constraints.

use string concatenation

__
fix Issue 13746 - formatValue of delegates
move format to std.format

The reason is to do not import `std.uni` tables, `std.string` and
probably `std.algorithm`. Note that format is used in CTFE code and
`Exception` handing.

 And it is more comfortable to import `format` from `std.format`.

std.format: clean imports (2)

remove import std.math : pow from std.uni

update scope imports in std.algorithm

update scope imports in std.exception

doFormat -> template

update scope imports in std.typecons

update scope imports in std.functional

update scope imports in std.range

update std.conv scope import

std.format: clean imports (2)

remove import std.math : pow from std.uni

update scope imports in std.algorithm

update scope imports in std.exception

doFormat -> template

update scope imports in std.typecons

update scope imports in std.functional

update scope imports in std.range

move sfromat

add public import of sformat

use std.uni
Merge pull request #2732 from 9il/move

move format to std.format
Merge pull request #2736 from 9il/erc

fix std/range/constraints.d static errors
Document new idiom for using Flag.
Merge pull request #2745 from 9il/fv

fix Issue 13746 - formatValue of delegates
Merge pull request #2741 from quickfur/flag

Document new idiom for using Flag.
std.conv.d - Fix typo
Merge pull request #2748 from JinShil/patch-1

std.conv.d - Fix typo
Add the capability to create tagged pointer and classes in bitmanip
fix constness of some char*
fix property enforcement
Add missing imports
Merge pull request #2749 from MartinNowak/curl

fix constness of some char*
Merge pull request #2752 from 9rnsr/fix_imports

Add missing imports
Merge pull request #2751 from 9rnsr/enforceProp

fix property enforcement
isNaN() is not a property

...so it shouldn't be used as one.
std.typecons: remake toString to template, clean module imports

update datetime unittests
avoid triggering issue 13745 in further improvements to come