docs: Move the unicode SECTION

Move the content to the new unicode.md file.

Helps: #3037

docs/reference/glib/glib.toml.in

@@ -65,6 +65,7 @@ content_files = [
   "markup.md",
   "goption.md",
   "data-structures.md",
+  "unicode.md",
 ]
 content_images = [
   "file-name-encodings.png",

docs/reference/glib/meson.build

@@ -163,6 +163,7 @@ expand_content_files = [
   'markup.md',
   'goption.md',
   'data-structures.md',
+  'unicode.md',
 ]
 
 glib_gir = meson.current_source_dir() / 'GLib-2.0.gir'

docs/reference/glib/unicode.md

@@ -0,0 +1,37 @@
+Title: Unicode
+SPDX-License-Identifier: LGPL-2.1-or-later
+SPDX-FileCopyrightText: 2011, 2014, 2023 Matthias Clasen
+SPDX-FileCopyrightText: 2020 Endless OS Foundation, LLC
+
+# Unicode support
+
+GLib has support for various aspects of Unicode, and provides a number of APIs for dealing
+with Unicode characters and strings.
+
+There are analogues of the traditional `ctype.h` character classification and case conversion
+functions, UTF-8 analogues of some string utility functions, functions to perform normalization,
+case conversion and collation on UTF-8 strings and finally functions to convert between the UTF-8,
+UTF-16 and UCS-4 encodings of Unicode.
+
+The implementations of the Unicode functions in GLib are based on the Unicode Character Data tables,
+which are available from [www.unicode.org](http://www.unicode.org/).
+
+ - Unicode 4.0 was added in GLib 2.8
+ - Unicode 4.1 was added in GLib 2.10
+ - Unicode 5.0 was added in GLib 2.12
+ - Unicode 5.1 was added in GLib 2.16.3
+ - Unicode 6.0 was added in GLib 2.30
+ - Unicode 6.1 was added in GLib 2.32
+ - Unicode 6.2 was added in GLib 2.36
+ - Unicode 6.3 was added in GLib 2.40
+ - Unicode 7.0 was added in GLib 2.42
+ - Unicode 8.0 was added in GLib 2.48
+ - Unicode 9.0 was added in GLib 2.50.1
+ - Unicode 10.0 was added in GLib 2.54
+ - Unicode 11.10 was added in GLib 2.58
+ - Unicode 12.0 was added in GLib 2.62
+ - Unicode 12.1 was added in GLib 2.62
+ - Unicode 13.0 was added in GLib 2.66
+ - Unicode 14.0 was added in GLib 2.71
+ - Unicode 15.0 was added in GLib 2.76
+