feat: symbol bar

[Sembauke]

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• I have read freeCodeCamp's contribution guidelines.
• My pull request has a descriptive title (not a vague title like Update index.md)

Closes #XXXXX

[Sembauke]

Thanks I will look into these issues on Thursday.

[Nirajn2311]

It would be better if some form of indication was given if there were symbols in the bar. I dint realise there was more symbols until I scrolled mistakenly. A shadow at the highlighted area could indicate there are more items. I believe we even have a package present in the code for it.

The fix for this always shows the white shadow on the right even if theres no item left to scroll to