Unicode superscript update

font/*/supsub.*: change superscript 1 into i; delete 2, 3
lib/keyboard: fix s1, s2, s3; add si
lib/unicode: add 2071
src/cmd/devdraw: update from lib/keyboard
diff --git a/lib/unicode b/lib/unicode
index 6d56856..3472c5f 100644
--- a/lib/unicode
+++ b/lib/unicode
@@ -3358,6 +3358,7 @@
 206e	national digit shapes
 206f	nominal digit shapes
 2070	superscript zero
+2071	superscript latin small letter i
 2074	superscript four
 2075	superscript five
 2076	superscript six