In townmaps (may be not only in Europe?) it is usual, to show the terminal of a streetcar-line with the line number encircled - like ⑤. This encircled numbers are defined in the Unicode as hexa from #2461 and following or decimal from 9312 and following. In the Unicode-list there are the encircled numbers 1 to 20. Also there are some encircled letters, if your lines are lettered.
In the ID-editor it is not possible, to give this encircled numbers into the name-tag directly only with the ALT-key-methode. So you please must look in an unicode-list and copy this character and paste it in the name-tag of your tram_stop-tag.
This encircled number logical looks smaller as the normal number. If you will be able to read this encircled number on the map, the character has to be in a greater grade. For this please add to your tag “railway=tram_stop” the tag “service=terminal”. Then the name of the tram-stop will appear in the histor-style in a greater grade as usual, so that the encircled number good is readable. In the standard-style this service tag will do nothing, there the tag is neutral. Visible in the histor-style this terminal-tags are in zoom 15; the normal name-tag of tram-stops in zoom 16.
Exemple for a streetcar-system with such terminals may be Aerwinya in Oakhill, Federal States - see [https://opengeofiction.net/#map=17/-37.80576/161.02969&layers=H]
Thanks to ChalieG for help.
Comment from coshatiuav on 24 May 2020 at 14:49
The unicode series for easy reference: