Some nits.
Fixed quoting in third paragraph of the findmatch() description.
diff --git a/Doc/lib/libmailcap.tex b/Doc/lib/libmailcap.tex
index da337bb..69329ee 100644
--- a/Doc/lib/libmailcap.tex
+++ b/Doc/lib/libmailcap.tex
@@ -8,16 +8,19 @@
types. (The name ``mailcap'' is derived from the phrase ``mail
capability''.) For example, a mailcap file might contain a line like
\samp{video/mpeg; xmpeg \%s}. Then, if the user encounters an email
-message or Web document with the MIME type video/mpeg, \code{\%s} will be
-replaced by a filename (usually one belonging to a temporary file) and
-the xmpeg program can be automatically started to view the file.
+message or Web document with the MIME type \mimetype{video/mpeg},
+\samp{\%s} will be replaced by a filename (usually one belonging to a
+temporary file) and the \program{xmpeg} program can be automatically
+started to view the file.
The mailcap format is documented in \rfc{1524}, ``A User Agent
Configuration Mechanism For Multimedia Mail Format Information,'' but
is not an Internet standard. However, mailcap files are supported on
most \UNIX{} systems.
-\begin{funcdesc}{findmatch}{caps, MIMEtype, key, filename, plist}
+\begin{funcdesc}{findmatch}{caps, MIMEtype%
+ \optional{, key\optional{,
+ filename\optional{, plist}}}}
Return a 2-tuple; the first element is a string containing the command
line to be executed
(which can be passed to \code{os.system()}), and the second element is
@@ -32,9 +35,9 @@
existing body data. See \rfc{1524} for a complete list of these
fields.
-\var{filename} is the filename to be substituted for \%s in the
+\var{filename} is the filename to be substituted for \samp{\%s} in the
command line; the default value is
-\file{/dev/null} which is almost certainly not what you want, so
+\code{'/dev/null'} which is almost certainly not what you want, so
usually you'll override it by specifying a filename.
\var{plist} can be a list containing named parameters; the default
@@ -43,7 +46,7 @@
parameter's value. Mailcap entries can contain
named parameters like \code{\%\{foo\}}, which will be replaced by the
value of the parameter named 'foo'. For example, if the command line
-\samp{showpartial \%\{id\} \%\{number\} \%\{total\}}
+\samp{showpartial \%\{id\}\ \%\{number\}\ \%\{total\}}
was in a mailcap file, and \var{plist} was set to \code{['id=1',
'number=2', 'total=3']}, the resulting command line would be
\code{"showpartial 1 2 3"}.