docs: remove link to asciinema

This image needs changing, so let's prepare by not linking to asciinema
anymore.

Change-Id: I15567325139fdf02bcca2bf2b1f1460d689cbfa4

README.md

@@ -23,7 +23,7 @@ Read our [documentation](https://gnpy.readthedocs.io/), learn from the demos, an
 
 This example demonstrates how GNPy can be used to check the expected SNR at the end of the line by varying the channel input power:
 
-[![Running a simple simulation example](https://telecominfraproject.github.io/oopt-gnpy/docs/images/transmission_main_example.svg)](https://asciinema.org/a/252295)
+![Running a simple simulation example](https://telecominfraproject.github.io/oopt-gnpy/docs/images/transmission_main_example.svg)
 
 GNPy can do much more, including acting as a Path Computation Engine, tracking bandwidth requests, or advising the SDN controller about a best possible path through a large DWDM network.
 Learn more about this [in the documentation](https://gnpy.readthedocs.io/).

docs/intro.rst

@@ -20,7 +20,6 @@ This example demonstrates how GNPy can be used to check the expected SNR at the
    :width: 100%
    :align: left
    :alt: Running a simple simulation example
-   :target: https://asciinema.org/a/252295
 
 By default, this script operates on a single span network defined in
 `gnpy/example-data/edfa_example_network.json <gnpy/example-data/edfa_example_network.json>`_