Update colophon to link to tc39 ecmarkup repo

Co-authored-by: Ujjwal Sharma <[email protected]>

Author: gesa

spec/colophon.html

@@ -1,5 +1,5 @@
 <emu-annex id="sec-colophon">
   <h1>Colophon</h1>
-  <p>This specification is authored on <a href="https://github.com/tc39/ecma402">GitHub</a> in a plaintext source format called <a href="https://github.com/bterlson/ecmarkup">Ecmarkup</a>. Ecmarkup is an HTML and Markdown dialect that provides a framework and toolset for authoring Ecma specifications in plaintext and processing the specification into a full-featured HTML rendering that follows the editorial conventions for this document. Ecmarkup builds on and integrates a number of other formats and technologies including <a href="https://github.com/rbuckton/grammarkdown">Grammarkdown</a> for defining syntax and <a href="https://github.com/domenic/ecmarkdown">Ecmarkdown</a> for authoring algorithm steps. PDF renderings of this specification are produced using <a href="https://www.princexml.com/">PrinceXML</a>.</p>
+  <p>This specification is authored on <a href="https://github.com/tc39/ecma402">GitHub</a> in a plaintext source format called <a href="https://github.com/tc39/ecmarkup">Ecmarkup</a>. Ecmarkup is an HTML and Markdown dialect that provides a framework and toolset for authoring Ecma specifications in plaintext and processing the specification into a full-featured HTML rendering that follows the editorial conventions for this document. Ecmarkup builds on and integrates a number of other formats and technologies including <a href="https://github.com/rbuckton/grammarkdown">Grammarkdown</a> for defining syntax and <a href="https://github.com/domenic/ecmarkdown">Ecmarkdown</a> for authoring algorithm steps. PDF renderings of this specification are produced using <a href="https://www.princexml.com/">PrinceXML</a>.</p>
   <p>Prior editions of this specification were authored using Word—the Ecmarkup source text that formed the basis of this edition was produced by converting the ECMAScript 2015 Word document to Ecmarkup using an automated conversion tool.</p>
 </emu-annex>