[css-text-3] Add myself as a co-editor

Author: frivoal

css-text-3/Overview.bs

@@ -13,6 +13,7 @@ Issue Tracking: Tracker http://www.w3.org/Style/CSS/Tracker/products/10
 Test Suite: http://test.csswg.org/suites/css3-text/nightly-unstable/
 Editor: Elika J. Etemad / fantasai, Invited Expert, http://fantasai.inkedblade.net/contact, w3cid 35400
 Editor: Koji Ishii, Invited Expert, kojiishi@gluesoft.co.jp, w3cid 45369
+Editor: Florian Rivoal, Invited Expert, https://florian.rivoal.net, w3cid 43241
 Abstract: This CSS3 module defines properties for text manipulation and specifies their processing model. It covers line breaking, justification and alignment, white space handling, and text transformation.
 At Risk: the ''full-width'' value of 'text-transform'
 At Risk: the <length> values of the 'tab-size' property