docs/library/ubluetooth.rst: Update char/desc flags.

Signed-off-by: Jim Mussared <jim.mussared@gmail.com>

docs/library/ubluetooth.rst

@@ -375,9 +375,9 @@ writes from a client to a given characteristic, use
     Each **descriptor** is a two-element tuple containing a UUID and a **flags**
     value.
 
-    The **flags** are a bitwise-OR combination of the
-    :data:`ubluetooth.FLAG_READ`, :data:`ubluetooth.FLAG_WRITE` and
-    :data:`ubluetooth.FLAG_NOTIFY` values defined below.
+    The **flags** are a bitwise-OR combination of the flags defined below. These
+    set both the behaviour of the characteristic (or descriptor) as well as the
+    security and privacy requirements.
 
     The return value is a list (one element per service) of tuples (each element
     is a value handle). Characteristics and descriptor handles are flattened
@@ -401,6 +401,25 @@ writes from a client to a given characteristic, use
 
     **Note:** Advertising must be stopped before registering services.
 
+    Available flags for characteristics and descriptors are::
+
+        from micropython import const
+        _FLAG_BROADCAST = const(0x0001)
+        _FLAG_READ = const(0x0002)
+        _FLAG_WRITE_NO_RESPONSE = const(0x0004)
+        _FLAG_WRITE = const(0x0008)
+        _FLAG_NOTIFY = const(0x0010)
+        _FLAG_INDICATE = const(0x0020)
+        _FLAG_AUTHENTICATED_SIGNED_WRITE = const(0x0040)
+
+        _FLAG_AUX_WRITE = const(0x0100)
+        _FLAG_READ_ENCRYPTED = const(0x0200)
+        _FLAG_READ_AUTHENTICATED = const(0x0400)
+        _FLAG_READ_AUTHORIZED = const(0x0800)
+        _FLAG_WRITE_ENCRYPTED = const(0x1000)
+        _FLAG_WRITE_AUTHENTICATED = const(0x2000)
+        _FLAG_WRITE_AUTHORIZED = const(0x4000)
+
 .. method:: BLE.gatts_read(value_handle, /)
 
     Reads the local value for this handle (which has either been written by
@@ -618,11 +637,3 @@ Constructor
 
     - A 16-bit integer. e.g. ``0x2908``.
     - A 128-bit UUID string. e.g. ``'6E400001-B5A3-F393-E0A9-E50E24DCCA9E'``.
-
-
-Constants
----------
-
-.. data:: ubluetooth.FLAG_READ
-          ubluetooth.FLAG_WRITE
-          ubluetooth.FLAG_NOTIFY