Correct small nits reported by Rob Hooft.
diff --git a/Doc/libgzip.tex b/Doc/libgzip.tex
index d444ebf..f832da7 100644
--- a/Doc/libgzip.tex
+++ b/Doc/libgzip.tex
@@ -21,7 +21,7 @@
The \file{gzip} file format includes the original filename of the
uncompressed file; when opening a \code{GzipFile} object for
writing, it can be set by the \var{filename} argument. The default
- value is \code{"GzippedFile"}.
+ value is an empty string.
\var{mode} can be either \code{'r'} or \code{'w'} depending on
whether the file will be read or written. \var{compresslevel} is an