Fix Issue 13212 - Windows line endings handled incorrectly by ddoc macros

Handle \r as \n in macro definitions to prevent a trailing carriage
return on a macro with an empty line following it.
Fix Issue 12745 - [Ddoc] Underscore is removed from numbers
Test 2 underscores
Fix counting unittest indent with Windows line endings
Fix removing trailing whitespace in documented unittest (Windows)
Fix reading ddoc ESCAPES on Windows
Merge pull request #3859 from ntrel/ddoc-test-cr

Fix Issue 13273 - ddoc can't handle \r in unittests and ESCAPES properly
fix Issue 13281 - Print type suffix of real/complex literals in pragma(msg) and error diagnostic

Use PrettyPrintVisitor::floatToBuffer from RealExp and ComplexExp::toChars().
The change in diag9375 is intended to print exact value.
[Refactoring] Remove unnecessary Expression::toChars() overridings
Merge pull request #3836 from ntrel/ddoc-digit-underscore

Fix Issue 12745 - [Ddoc] Underscore is removed from numbers
Merge pull request #3868 from 9rnsr/fix13281

Issue 13281 - Print type suffix of real/complex literals in pragma(msg) and error diagnostic
Merge pull request #3829 from ntrel/macro-cr

Fix Issue 13212 - Trailing Windows line endings not stripped from .ddoc macros