Fix unicode.SimpleFold(r)

[wallclockbuilder]

We expect that
Right now
unicode.SimpleFold('k') == '\u212A'
*\u212A is 'K' the Kelvin char
This is not intuitive for ASCII simple folding.
Fix it so that
unicode.SimpleFold('k') == 'K'

[wallclockbuilder]

lowercase letter 'k' is \u004B
uppercase lettter 'K' is \u006B

[wallclockbuilder]

Simply mapping [a-z] to [A-Z] should work for most simple ASCII-only text documents.

[wallclockbuilder]

the Unicode 6.0 spec has this to say about U+212A (KELVIN SIGN):

Three letterlike symbols have been given canonical equivalence to regular letters: U+2126 OHM SIGN, U+212A KELVIN SIGN, and U+212B ANGSTROM SIGN. In all three instances, the regular letter should be used. If text is normalized according to Unicode Standard Annex #15, “Unicode Normalization Forms,” these three characters will be replaced by their regular equivalents.

In other words, you shouldn't really be using U+212A, you should be using U+004B (LATIN CAPITAL LETTER K) instead, and if you normalize your Unicode text, U+212A should be replaced with U+004B.

[wallclockbuilder]

Three letterlike symbols have been given canonical equivalence to regular letters:
U+2126 ohm sign,
U+212A kelvin sign, and
U+212B angstrom sign.

In all three instances, the regular letter should be used. If text is normalized according to Unicode Standard Annex#15, “Unicode Normalization Forms,” these three characters will be replaced by their regular equivalents.

http://www.unicode.org/versions/Unicode6.0.0/ch15.pdf

[wallclockbuilder]

Unicode 8.0 Character Code Charts
The most current code chart containing U+212A is:

http://www.unicode.org/charts/PDF/U2100.pdf 

And it specs that the Kelvin sign is equivalent to the Latin Capital letter k.
Heres a snapshot.