Document the default for tabsize in expandtabs().

diff --git a/Doc/lib/libstring.tex b/Doc/lib/libstring.tex
index 4bf29032a1fa203b7695a49f77913447619ebdc8..442486369b17944633490a388ba8d4673fb72590 100644 (file)
--- a/Doc/lib/libstring.tex
+++ b/Doc/lib/libstring.tex
@@ -102,12 +102,12 @@ The functions defined in this module are:
   trailing whitespace.
 \end{funcdesc}
 
-\begin{funcdesc}{expandtabs}{s, tabsize}
+\begin{funcdesc}{expandtabs}{s, \optional{tabsize}}
   Expand tabs in a string, i.e.\ replace them by one or more spaces,
   depending on the current column and the given tab size.  The column
   number is reset to zero after each newline occurring in the string.
   This doesn't understand other non-printing characters or escape
-  sequences.
+  sequences.  The tab size defaults to 8.
 \end{funcdesc}
 
 \begin{funcdesc}{find}{s, sub\optional{, start\optional{,end}}}