Add Sindhi (sd-sind) to language-data

[Siddharth-Talreja]

This is in connection to phabricator task https://phabricator.wikimedia.org/T428126.
It is a continuation of PR 504. As the other contributor seems to have left this task, I have made the changes here

[srish]

@Siddharth-Talreja There is already a work-in-progress PR on the same topic here: #504, so I'll have to close this for now. Thanks for taking a stab at it, though.

[Siddharth-Talreja]

@Siddharth-Talreja There is already a work-in-progress PR on the same topic here: #504, so I'll have to close this for now. Thanks for taking a stab at it, though.

@srish Ok, but in case the owner of the PR 504 doesn't continue as stated by them on phabricator, what can be done next?

[srish]

@Siddharth-Talreja Ahha, my bad. I didn't notice the comment earlier. I will take a look at yours now. Thanks a lot for sending the PR!

[srish]

@Siddharth-Talreja Thanks for the PR!