Quote value with leading or trailing Unicode whitespace

[rootvector2]

printWithQuotes decides MINIMAL-mode encapsulation from the first and last character, but only against ascii bounds: c <= Constants.COMMENT for the leading char and isTrimChar (c <= ' ') for the trailing one. The parser's ignoreSurroundingSpaces strips any Character.isWhitespace on read, and several whitespace code points sit above ' ' (U+3000 ideographic space, U+2028/U+2029, U+2003, U+1680, U+205F, U+2000..U+200A). A value bounded by one of them, such as 　a　, is written unquoted and read back trimmed to a. Quote when the first or last character is Character.isWhitespace, matching what the reader trims. isTrimChar is left alone since it is shared with the getTrim path that mirrors String.trim.

Found while round-tripping unicode whitespace through the printer with ignoreSurroundingSpaces.

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