""
''
"foo"
'foo'
"'foo'"
'"bar"'
"  # comment  "

----------------------------------------------------

[
	["string", "\"\""],
	["string", "''"],
	["string", "\"foo\""],
	["string", "'foo'"],
	["string", "\"'foo'\""],
	["string", "'\"bar\"'"],
	["string", "\"  # comment  \""]
]

----------------------------------------------------

Checks for single-quoted and double-quoted strings.