nothrow for Schedulder

- require nothrow for thisInfo, yield

- make Condition methods nothrow
Mark methods in std.range.cycle for static array as system
Make Cycle.this system and other methods safe
Remove redundant alias
Move a modulo operation into the trusted function
Merge pull request #2647 from tom-tan/system-range-cycle-for-sarray

Mark methods in std.range.Cycle for static array as system
Mark std.range.cycle for static array and their unittests as system
Extend groupBy to handle non-equivalence relations.

Update DDocs.

Add unittest for 13595.
Use flag enum instead of bool.

To prevent Boolean Blindness.
Do reflexivity check in assert mode if predicate is claimed to be equivalence relation.
Use Flag instead of single-use enum.
Merge pull request #2704 from MartinNowak/nothrowScheduler

nothrow for Schedulder
Rewrite of Phobos index page.

Make it more useful than the current outdated and irrelevant philosophy
page.
Remove useless link to obsolete wiki.
Rename IsEquivRelation to EquivRelation.
make nested foreach over TypeTuple bodies into lambdas to avoid huge functions
Merge pull request #2767 from rainers/unittest_smallfuncs

Reduce compilation time for phobos unittests by about 25%
code formatting, use sink

update docs, style, use thread:id scheme

use MessageBox hash, remove running thread

use mbox address

moved import
Supplemental fix for issue 13783 in std.parallelism

`auto f(ref ubyte);` should not take an lvalue of `enum E : ubyte`.
Fixing 13783 will disallow the accepts-invalid bug.
Use version-specific navbar when building docs.