Add tests for properties file lexer

lexers/testdata/properties.actual

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+# You are reading a comment in ".properties" file.
+! The exclamation mark can also be used for comments.
+# Lines with "properties" contain a key and a value separated by a delimiting character.
+# There are 3 delimiting characters: '=' (equal), ':' (colon) and whitespace (space, \t and \f).
+website = https://en.wikipedia.org/
+language : English
+# White space that appears between the key, the value and the delimiter is ignored.
+# This means that the following are equivalent (other than for readability).
+hello=hello
+hello = hello
+# Keys with the same name will be overwritten by the key that is the furthest in a file.
+# For example the final value for "duplicateKey" will be "second".
+duplicateKey = first
+duplicateKey = second
+# If you need to add newlines and carriage returns, they need to be escaped using \n and \r respectively.
+# You can also optionally escape tabs with \t for readability purposes.
+valueWithEscapes = This is a newline\n and a carriage return\r and a tab\t.
+# You can also use Unicode escape characters (maximum of four hexadecimal digits).
+# In the following example, the value for "encodedHelloInJapanese" is "こんにちは".
+encodedHelloInJapanese = \u3053\u3093\u306b\u3061\u306f
+# But with more modern file encodings like UTF-8, you can directly use supported characters.
+helloInJapanese = こんにちは

lexers/testdata/properties.expected

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+[
+  {"type":"CommentSingle","value":"# You are reading a comment in \".properties\" file."},
+  {"type":"Text","value":"\n"},
+  {"type":"CommentSingle","value":"! The exclamation mark can also be used for comments."},
+  {"type":"Text","value":"\n"},
+  {"type":"CommentSingle","value":"# Lines with \"properties\" contain a key and a value separated by a delimiting character."},
+  {"type":"Text","value":"\n"},
+  {"type":"CommentSingle","value":"# There are 3 delimiting characters: '=' (equal), ':' (colon) and whitespace (space, \\t and \\f)."},
+  {"type":"Text","value":"\n"},
+  {"type":"NameAttribute","value":"website"},
+  {"type":"Text","value":" "},
+  {"type":"Operator","value":"="},
+  {"type":"Text","value":" "},
+  {"type":"LiteralString","value":"https://en.wikipedia.org/"},
+  {"type":"Text","value":"\n"},
+  {"type":"NameAttribute","value":"language"},
+  {"type":"Text","value":" "},
+  {"type":"Operator","value":":"},
+  {"type":"Text","value":" "},
+  {"type":"LiteralString","value":"English"},
+  {"type":"Text","value":"\n"},
+  {"type":"CommentSingle","value":"# White space that appears between the key, the value and the delimiter is ignored."},
+  {"type":"Text","value":"\n"},
+  {"type":"CommentSingle","value":"# This means that the following are equivalent (other than for readability)."},
+  {"type":"Text","value":"\n"},
+  {"type":"NameAttribute","value":"hello"},
+  {"type":"Operator","value":"="},
+  {"type":"LiteralString","value":"hello"},
+  {"type":"Text","value":"\n"},
+  {"type":"NameAttribute","value":"hello"},
+  {"type":"Text","value":" "},
+  {"type":"Operator","value":"="},
+  {"type":"Text","value":" "},
+  {"type":"LiteralString","value":"hello"},
+  {"type":"Text","value":"\n"},
+  {"type":"CommentSingle","value":"# Keys with the same name will be overwritten by the key that is the furthest in a file."},
+  {"type":"Text","value":"\n"},
+  {"type":"CommentSingle","value":"# For example the final value for \"duplicateKey\" will be \"second\"."},
+  {"type":"Text","value":"\n"},
+  {"type":"NameAttribute","value":"duplicateKey"},
+  {"type":"Text","value":" "},
+  {"type":"Operator","value":"="},
+  {"type":"Text","value":" "},
+  {"type":"LiteralString","value":"first"},
+  {"type":"Text","value":"\n"},
+  {"type":"NameAttribute","value":"duplicateKey"},
+  {"type":"Text","value":" "},
+  {"type":"Operator","value":"="},
+  {"type":"Text","value":" "},
+  {"type":"LiteralString","value":"second"},
+  {"type":"Text","value":"\n"},
+  {"type":"CommentSingle","value":"# If you need to add newlines and carriage returns, they need to be escaped using \\n and \\r respectively."},
+  {"type":"Text","value":"\n"},
+  {"type":"CommentSingle","value":"# You can also optionally escape tabs with \\t for readability purposes."},
+  {"type":"Text","value":"\n"},
+  {"type":"NameAttribute","value":"valueWithEscapes"},
+  {"type":"Text","value":" "},
+  {"type":"Operator","value":"="},
+  {"type":"Text","value":" "},
+  {"type":"LiteralString","value":"This is a newline\\n and a carriage return\\r and a tab\\t."},
+  {"type":"Text","value":"\n"},
+  {"type":"CommentSingle","value":"# You can also use Unicode escape characters (maximum of four hexadecimal digits)."},
+  {"type":"Text","value":"\n"},
+  {"type":"CommentSingle","value":"# In the following example, the value for \"encodedHelloInJapanese\" is \"こんにちは\"."},
+  {"type":"Text","value":"\n"},
+  {"type":"NameAttribute","value":"encodedHelloInJapanese"},
+  {"type":"Text","value":" "},
+  {"type":"Operator","value":"="},
+  {"type":"Text","value":" "},
+  {"type":"LiteralString","value":"\\u3053\\u3093\\u306b\\u3061\\u306f"},
+  {"type":"Text","value":"\n"},
+  {"type":"CommentSingle","value":"# But with more modern file encodings like UTF-8, you can directly use supported characters."},
+  {"type":"Text","value":"\n"},
+  {"type":"NameAttribute","value":"helloInJapanese"},
+  {"type":"Text","value":" "},
+  {"type":"Operator","value":"="},
+  {"type":"Text","value":" "},
+  {"type":"LiteralString","value":"こんにちは"},
+  {"type":"Text","value":"\n"}
+]