docs: Move the GType SECTION

Move the contents to the new types.md files.

Helps: #3037

gobject/gtype.c

@@ -44,65 +44,6 @@
 #define	IF_DEBUG(debug_type)	if (_g_type_debug_flags & G_TYPE_DEBUG_ ## debug_type)
 #endif
 
-/**
- * SECTION:gtype
- * @short_description: The GLib Runtime type identification and
- *     management system
- * @title:Type Information
- *
- * The GType API is the foundation of the GObject system. It provides the
- * facilities for registering and managing all fundamental data types,
- * user-defined object and interface types.
- *
- * For type creation and registration purposes, all types fall into one of
- * two categories: static or dynamic.  Static types are never loaded or
- * unloaded at run-time as dynamic types may be.  Static types are created
- * with g_type_register_static() that gets type specific information passed
- * in via a #GTypeInfo structure.
- *
- * Dynamic types are created with g_type_register_dynamic() which takes a
- * #GTypePlugin structure instead. The remaining type information (the
- * #GTypeInfo structure) is retrieved during runtime through #GTypePlugin
- * and the g_type_plugin_*() API.
- *
- * These registration functions are usually called only once from a
- * function whose only purpose is to return the type identifier for a
- * specific class.  Once the type (or class or interface) is registered,
- * it may be instantiated, inherited, or implemented depending on exactly
- * what sort of type it is.
- *
- * There is also a third registration function for registering fundamental
- * types called g_type_register_fundamental() which requires both a #GTypeInfo
- * structure and a #GTypeFundamentalInfo structure but it is seldom used
- * since most fundamental types are predefined rather than user-defined.
- *
- * Type instance and class structs are limited to a total of 64 KiB,
- * including all parent types. Similarly, type instances' private data
- * (as created by G_ADD_PRIVATE()) are limited to a total of
- * 64 KiB. If a type instance needs a large static buffer, allocate it
- * separately (typically by using #GArray or #GPtrArray) and put a pointer
- * to the buffer in the structure.
- *
- * As mentioned in the [GType conventions][gtype-conventions], type names must
- * be at least three characters long. There is no upper length limit. The first
- * character must be a letter (a–z or A–Z) or an underscore (‘_’). Subsequent
- * characters can be letters, numbers or any of ‘-_+’.
- *
- * # Runtime Debugging
- *
- * When `G_ENABLE_DEBUG` is defined during compilation, the GObject library
- * supports an environment variable `GOBJECT_DEBUG` that can be set to a
- * combination of flags to trigger debugging messages about
- * object bookkeeping and signal emissions during runtime.
- *
- * The currently supported flags are:
- *  - `objects`: Tracks all #GObject instances in a global hash table called
- *    `debug_objects_ht`, and prints the still-alive objects on exit.
- *  - `instance-count`: Tracks the number of instances of every #GType and makes
- *    it available via the g_type_get_instance_count() function.
- *  - `signals`: Currently unused.
- */
-
 
 /* NOTE: some functions (some internal variants and exported ones)
  * invalidate data portions of the TypeNodes. if external functions/callbacks