Add textsec support for confusable characters

* admin/notes/unicode: Note the confusables.txt file.
* admin/unidata/Makefile.in (${unidir}/uni-confusable.el):
Generate the confusable file.

* admin/unidata/README (https): Add confusables.txt.

* admin/unidata/confusables.txt: New file.

* admin/unidata/unidata-gen.el (unidata-gen-confusable): Parse the
confusables.txt file.

* lisp/international/textsec.el (textsec-ascii-confusable-p)
(textsec-unconfuse-string): New functions.

1 files changed, 2 insertions, 1 deletions

diff --git a/admin/notes/unicode b/admin/notes/unicode
index 43e11782d25..98dc01bc08f 100644
--- a/admin/notes/unicode
+++ b/admin/notes/unicode
@@ -19,6 +19,7 @@ Emacs uses the following files from the Unicode Character Database
   . ScriptExtensions.txt
   . Scripts.txt
   . SpecialCasing.txt
+  . confusables.txt
   . emoji-data.txt
   . emoji-zwj-sequences.txt
   . emoji-sequences.txt
@@ -27,7 +28,7 @@ Emacs uses the following files from the Unicode Character Database
 Emacs also uses the file emoji-test.txt which should be imported from
 the Unicode's Public/emoji/ directory.
 
-First, the first 13 files and emoji-test.txt need to be copied into
+First, the first 14 files and emoji-test.txt need to be copied into
 admin/unidata/, and the file https://www.unicode.org/copyright.html
 should be copied over copyright.html in admin/unidata (some of them
 might need trailing whitespace removed before they can be committed to