Adding Demitri Lawrence to credits

Author: gcarcassi

book.tex

@@ -884,7 +884,7 @@ \section{Set theory}
 Additional subject-matter advisors (Math): \\ \textit{\footnotesize review prompted significant technical improvements} & Daniel Burns, Alejandro Uribe, Alexander Wilce (Ch. II.4) \\
 (Phil):  & Josh Hunt (Ch. II.1) \\
 & \\
-Subject-matter reviewers (Math): \\ \textit{\footnotesize review prompted technical fixes} & Sharif Velasquez (Ch. II.1), Bart Westra (Ch. II.3), Matt Insall, Junde Song (Ch. II.4) \\
+Subject-matter reviewers (Math): \\ \textit{\footnotesize review prompted technical fixes} & Sharif Velasquez (Ch. II.1), Bart Westra (Ch. II.3), Matt Insall, Demitri Lawrence, Junde Song (Ch. II.4) \\
 & \\
 & \\
 Diagrams and figures: \\ \textit{\footnotesize contributed one or more} & Matteo Carcassi (Ch. I.1), Saja Gherri (Ch. II.1,II.2), Tobias Thrien (Ch. II.4) \\