Fix two small errors in argument lists.
diff --git a/Doc/lib/libdecimal.tex b/Doc/lib/libdecimal.tex
index ffc3363..a0c7bde 100644
--- a/Doc/lib/libdecimal.tex
+++ b/Doc/lib/libdecimal.tex
@@ -713,8 +713,8 @@
\constant{NaN}.
\end{methoddesc}
-\begin{methoddesc}{sqrt}{}
- Return the square root to full precision.
+\begin{methoddesc}{sqrt}{x}
+ Return the square root of \var{x} to full precision.
\end{methoddesc}
\begin{methoddesc}{subtract}{x, y}
@@ -734,7 +734,7 @@
or \constant{Rounded}.
\end{methoddesc}
-\begin{methoddesc}{to_sci_string}{}
+\begin{methoddesc}{to_sci_string}{x}
Converts a number to a string using scientific notation.
\end{methoddesc}