Don't use nullptr to represent empty string.
Have a static constexpr length 1 string.
Merge remote-tracking branch 'origin/master'

Conflicts:
	string_view
Merge remote-tracking branch 'origin/master'
Move the feature testing busy boxen to the tr2 playground.
Add features test work.
Merge remote-tracking branch 'origin/master'
Merge remote-tracking branch 'origin/master'
Merge remote-tracking branch 'origin/master'
Merge remote-tracking branch 'origin/master'
Add PR59876 tests - another decltype literal operator problem.
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Merge remote-tracking branch 'origin/master'
Merge remote-tracking branch 'origin/master'
Got search to compile.
Added tester.