New index entries.
diff --git a/Doc/lib/libsys.tex b/Doc/lib/libsys.tex
index 932520d..3138180 100644
--- a/Doc/lib/libsys.tex
+++ b/Doc/lib/libsys.tex
@@ -176,6 +176,8 @@
\begin{datadesc}{ps1}
\dataline{ps2}
+\index{interpreter prompts}
+\index{prompts, interpreter}
Strings specifying the primary and secondary prompt of the
interpreter. These are only defined if the interpreter is in
interactive mode. Their initial values in this case are
diff --git a/Doc/libsys.tex b/Doc/libsys.tex
index 932520d..3138180 100644
--- a/Doc/libsys.tex
+++ b/Doc/libsys.tex
@@ -176,6 +176,8 @@
\begin{datadesc}{ps1}
\dataline{ps2}
+\index{interpreter prompts}
+\index{prompts, interpreter}
Strings specifying the primary and secondary prompt of the
interpreter. These are only defined if the interpreter is in
interactive mode. Their initial values in this case are