refactor(paper.evo.relax): fix contraction of 'is'

Author: JohelEGP

number_concepts/paper-evolution.tex

@@ -7,7 +7,7 @@
 
 \pnum
 The concepts are known to be over-constraining for templates like \hrefX{\tcode{boost::hana::int_c}}.
-The feedback from \hrefVII{} suggests its time for the hierarchy to be refactored.
+The feedback from \hrefVII{} suggests it is time for the hierarchy to be refactored.
 This will allow a wider variety of number templates that make interesting uses of the type system.
 
 \rSec1[paper.evo.ops]{More operations}