doc: fix typo in markdown

Author: pdubroy

doc/used-by.md

@@ -5,7 +5,7 @@ Ohm has been around for over 10 years, and is used in a wide variety of interest
 - The [The ERC-funded OnePub project](https://cordis.europa.eu/project/id/101113339) is using Ohm in a collaborative, local-first editor for [Asciidoc](https://asciidoc.org/) documents.
 - [Ambsheets, a spreadsheet for exploring scenarios](https://www.inkandswitch.com/ambsheets/notebook/) by Ink & Switch.
 - [SchuBu](https://de.schubu.org/p768/programmieren), a free-to-use digital schoolbook in use by over 100.000 students in Austria, uses Ohm for the Gambu-Script language.
-- [Bruno](https://usebruno.com/) is an open source IDE for exploring and testing APIs. They used Ohm to develop [the Bru markup language]((https://docs.usebruno.com/bru-lang/overview).
+- [Bruno](https://usebruno.com/) is an open source IDE for exploring and testing APIs. They used Ohm to develop [the Bru markup language](https://docs.usebruno.com/bru-lang/overview).
 - [WELLE](https://www.nime.org/proceedings/2020/nime2020_paper114.pdf) by Jens Vetter from Kunstuniversität Linz, is a web-based music environment for the blind.
 - [Wildcard](https://www.geoffreylitt.com/wildcard/), by Geoffrey Litt from MIT, is a browser extension that empowers anyone to modify websites to meet their own specific needs. It uses Ohm for its spreadsheet language.
 - [turtle.audio](http://turtle.audio) is an audio environment where simple text commands generate lines that can play music.