docs: Move the base64 SECTION

Move it to a separate file as there is no struct to hang the docs off.

Signed-off-by: Philip Withnall <pwithnall@gnome.org>

Helps: #3037

docs/reference/glib/base64.md

@@ -0,0 +1,20 @@
+Title: Base64 Encoding
+SPDX-License-Identifier: LGPL-2.1-or-later
+SPDX-FileCopyrightText: 2006, 2009 Matthias Clasen
+
+# Base64 Encoding
+
+Base64 is an encoding that allows a sequence of arbitrary bytes to be
+encoded as a sequence of printable ASCII characters. For the definition
+of Base64, see [RFC 1421](http://www.ietf.org/rfc/rfc1421.txt) or
+[RFC 2045](http://www.ietf.org/rfc/rfc2045.txt).
+Base64 is most commonly used as a MIME transfer encoding for email.
+
+GLib supports incremental encoding using [func@GLib.base64_encode_step] and
+[func@GLib.base64_encode_close]. Incremental decoding can be done with
+[func@GLib.base64_decode_step]. To encode or decode data in one go, use
+[func@GLib.base64_encode] or [func@GLib.base64_decode]. To avoid memory
+allocation when decoding, you can use [func@GLib.base64_decode_inplace].
+
+Support for Base64 encoding was added in GLib 2.12.
+

docs/reference/glib/glib.toml.in

@@ -63,6 +63,7 @@ content_files = [
   "testing.md",
   "threads.md",
   "markup.md",
+  "base64.md",
   "goption.md",
   "data-structures.md",
   "unicode.md",

docs/reference/glib/meson.build

@@ -145,6 +145,7 @@ endif
 
 # gi-docgen version
 expand_content_files = [
+  'base64.md',
   'building.md',
   'character-set.md',
   'compiling.md',