Recommend using portable std.ascii.newline for line terminator

Also document 'lines' constructor.
Note that readln() cannot support string terminators
Define isNaN deprecation for integers

Also cleans isNaN unit tests
Add more integer isXXX deprecations

Also implementation is changed to forward to floating point signature
instead of a stub to exactly match old behaviour.
fix property enforcement
DList: remove opBinary(string)(DList)
Don't use std.ascii.newline with text mode
Remove workaround for issue 12164.
localize some imports
Merge pull request #2374 from Dicebot/nan-deprecation

[reg] isNaN deprecation for integers
Merge pull request #2395 from MartinNowak/localizeImports

localize some imports
Merge pull request #2394 from Kapps/remove12164wa

Remove workaround for issue 12164.
Merge pull request #2390 from 9rnsr/enforceProp

fix property enforcement
std.bitmanip BitArray refactor and various fixes
Merge pull request #2249 from Safety0ff/bitarrayrefact

std.bitmanip BitArray refactor
Merge pull request #2364 from ntrel/stdio-newline

[docs] Recommend std.ascii.newline for portable line terminator in std.stdio
std.getopt: Remove opinionated comment regarding option bundling

The behavior is standard in UNIX programs. Although it wouldn't make sense
to change the default at this point, D documentation is not a good place
for criticizing established standards.
Merge pull request #2398 from CyberShadow/getopt-bundling-doc

std.getopt: Remove opinionated comment regarding option bundling
Replace use of T.min to determine signedness with std.traits.isUnsigned.
Merge pull request #2386 from MetaLang/variant-remove-float-min

Fix Issue 13230: std.variant.Variant Uses Deprecated .min Property in opArithmetic When T is a Floating Point Type