media: dev-decoder.rst: small fixes

Add missing periods at the end of two sentences.

Although mandatory -> Although not mandatory
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Reviewed-by: Michael Tretter <m.tretter@pengutronix.de>
Acked-by: Tomasz Figa <tfiga@chromium.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

Documentation/userspace-api/media/v4l/dev-decoder.rst

@@ -247,7 +247,7 @@ Querying Capabilities
 Initialization
 ==============
 
-1. Set the coded format on ``OUTPUT`` via :c:func:`VIDIOC_S_FMT`
+1. Set the coded format on ``OUTPUT`` via :c:func:`VIDIOC_S_FMT`.
 
    * **Required fields:**
 
@@ -803,7 +803,7 @@ it may be affected as per normal decoder operation.
    * The decoder will drop all the pending ``OUTPUT`` buffers and they must be
      treated as returned to the client (following standard semantics).
 
-2. Restart the ``OUTPUT`` queue via :c:func:`VIDIOC_STREAMON`
+2. Restart the ``OUTPUT`` queue via :c:func:`VIDIOC_STREAMON`.
 
    * **Required fields:**
 
@@ -1059,7 +1059,7 @@ sequence was started.
    ``V4L2_DEC_CMD_STOP`` again while the drain sequence is in progress and they
    will fail with -EBUSY error code if attempted.
 
-   Although mandatory, the availability of decoder commands may be queried
+   Although not mandatory, the availability of decoder commands may be queried
    using :c:func:`VIDIOC_TRY_DECODER_CMD`.
 
 End of Stream