Issue 8370 - Fix deprecated message during Linux Phobos build.

This change fixes Linux builds only. Other Posix based OS's will still use the deprecated alias from the Posix module. (This is the same behavior as the garbage collector module.)
Add documented unit tests for formatValue()

Add example showing how to forward format specifiers.
Add example highlighting the similarity with formattedWrite(), and
comparing their use.

Change /** */ for /// and add $(D formatValue)

Replace /** */ with /++ +/
std.algorithm.remove: Fix constraints and change popBack loop to popBackN
std.algorithm.remove: Change pop____N to pop____Exactly
Updated std.format documentation of width and precision specifiers
Merge pull request #2302 from dcarp/master

Updated std.format documentation of width and precision specifiers
fix Issue 10916 - toHash on VariantN not being recognised

Make VariantN.toHash() const nothrow @safe. Assume that `VariantN.type` property is @safe nothrow.
Remove redundant Tuple.opEquals

Today struct type equality `a == b` is expanded to `a.tupleof == b.tupleof`, so opEquals method is unnecessary for `std.tyoecons.Tuple`.
Merge pull request #2303 from 9rnsr/fix_hash

Tweak Tuple and Variant for correct hashing
Merge pull request #2256 from Safety0ff/popbackn

std.algorithm.remove: Fix constraints and change popBack loop to popBackN
Fix issue 12455 [reg]Bad lowercase mapping for 'LATIN CAPITAL LETTER I WITH DOT ABOVE'

Also as part of a fix restores a test case in string.d
to exactly match older behaviour.

Some extended greek is not upper but title case, yet changes on toUpper.
Merge pull request #2296 from Element-126/doc_formatValue_add_example

Add documentation examples for formatValue()
std.json.JSONValue toString is now const
Merge pull request #2292 from markisaa/constToString

Issue 13015 - std.json.JSONValue's toString is now const
Merge pull request #2304 from DmitryOlshansky/issue-12455

[REG]Fix issue 12455 Bad lowercase mapping for 'LATIN CAPITAL LETTER I W...
fix Issue 13056 - [2.066.0-b1] Regression: Error: template std.path.baseName cannot deduce function from argument types !()(DirEntry)
Changed tabs to spaces
Merge pull request #2295 from adamsaka/issue_8370

Issue 8370 - Fix deprecated message during Linux Phobos build.
Merge pull request #2306 from WalterBright/fix13056

fix Issue 13056 - [2.066.0-b1] Regression: Error: template std.path.base...