“No data” messages are out of date

[wchargin]

“No data” messages are out of date

The messages that appear when you select a dashboard for which no data is loaded are out of date. From a quick skim:

• Some links point to “the TensorBoard tutorial” putatively located at https://www.tensorflow.org/get_started/summaries_and_tensorboard, but that link now redirects to the general TensorFlow tutorials subsite, https://www.tensorflow.org/tutorials.
• Likewise for the “graph visualizer tutorial”.
• The graphs dashboard suggests creating a tf.summary.FileWriter and calling its add_graph method; this class does not exist in TF 2.0 (except via compat.v1), and graph tracing is now done via the tf.summary.trace_* functions.
• The profile dashboard’s first tutorial link is broken (404): https://colab.research.google.com/github/tensorflow/tensorboard/blob/master/docs/r2/tensorboard_profiling_keras.ipynb
• Beholder.
• The projector dashboard doesn’t have the necessary recommendations for TF 2.0 (cf. #2471).
• Some dashboards have no “no-data” help text at all: PR curves, HParams.

[ManishAradwad]

@wchargin @nfelt I'd like to fix this issue. Can you plz point me where should I make changes?