Rename 'ArXiv' to 'arXiv' in add-entry-using-id.md docs section (#605)

Co-authored-by: Oliver Kopp <kopp.dev@gmail.com>

Author: pKondaszewski

en/collect/add-entry-using-an-id.md

@@ -18,13 +18,13 @@ Sometimes the new entry contains a `url` field. This field usually points to the
 You can also add an entry by simply pasting its BibTex or its DOI from your clipboard to the maintable.
 {% endhint %}
 
-## Supported databases
+## Supported catalogs
 
-### Arxiv
+### arXiv
 
-[ArXiv](https://arxiv.org) is a repository of scientific preprints in the fields of mathematics, physics, astronomy, computer science, quantitative biology, statistics, and quantitative finance ([Wikipedia](https://en.wikipedia.org/wiki/ArXiv)).
+[arXiv](https://arxiv.org) is a repository of scientific preprints in the fields of mathematics, physics, astronomy, computer science, quantitative biology, statistics, and quantitative finance ([Wikipedia](https://en.wikipedia.org/wiki/ArXiv)).
 
-ID search is carried out using the [ArXiv identifier](https://arxiv.org/help/arxiv_identifier).
+ID search is carried out using the [arXiv identifier](https://arxiv.org/help/arxiv_identifier).
 
 ### Crossref