docs: Update generics.tex

Author: slavapestov

docs/Generics/chapters/generic-environments.tex renamed to docs/Generics/chapters/archetypes.tex

@@ -2,7 +2,7 @@
 
 \begin{document}
 
-\chapter{Concrete Conformances}\label{concrete conformances}
+\chapter[]{Concrete Conformances}\label{concrete conformances}
 
 \ifWIP
 TODO:
@@ -15,7 +15,7 @@ \chapter{Concrete Conformances}\label{concrete conformances}
 \end{itemize}
 \fi
 
-\section{Type Witnesses}\label{rqm type witnesses}
+\section[]{Type Witnesses}\label{rqm type witnesses}
 
 \IndexTwoFlag{debug-requirement-machine}{concretize-nested-types}
 
@@ -29,7 +29,7 @@ \section{Type Witnesses}\label{rqm type witnesses}
 \end{itemize}
 \fi
 
-\section{Recursive Conformances}
+\section[]{Recursive Conformances}
 
 \ifWIP
 TODO:
@@ -46,11 +46,13 @@ \section{Recursive Conformances}
 
 \IndexFlag{enable-requirement-machine-opaque-archetypes}
 
-\section{Concrete Contraction}\label{concrete contraction}
+\section[]{Concrete Contraction}\label{concrete contraction}
 
 \IndexFlag{disable-requirement-machine-concrete-contraction}
 \IndexTwoFlag{debug-requirement-machine}{concrete-contraction}
 
+\IndexDefinition{concrete contraction}
+
 \ifWIP
 TODO:
 \begin{itemize}
@@ -63,6 +65,6 @@ \section{Concrete Contraction}\label{concrete contraction}
 \end{itemize}
 \fi
 
-\section{Source Code Reference}
+\section[]{Source Code Reference}
 
-\end{document}
+\end{document}