Re-order some method descriptions for a more logical grouping.

(Based on reader comment!)

Doc/lib/libmultifile.tex

@@ -39,19 +39,6 @@ own pattern for section-divider and end-marker lines.
 
 A \class{MultiFile} instance has the following methods:
 
-\begin{methoddesc}{push}{str}
-Push a boundary string.  When an appropriately decorated version of
-this boundary is found as an input line, it will be interpreted as a
-section-divider or end-marker.  All subsequent
-reads will return the empty string to indicate end-of-file, until a
-call to \method{pop()} removes the boundary a or \method{next()} call
-reenables it.
-
-It is possible to push more than one boundary.  Encountering the
-most-recently-pushed boundary will return EOF; encountering any other
-boundary will raise an error.
-\end{methoddesc}
-
 \begin{methoddesc}{readline}{str}
 Read a line.  If the line is data (not a section-divider or end-marker
 or real EOF) return it.  If the line matches the most-recently-stacked
@@ -71,18 +58,6 @@ Read all lines, up to the next section.  Return them as a single
 (multiline) string.  Note that this doesn't take a size argument!
 \end{methoddesc}
 
-\begin{methoddesc}{next}{}
-Skip lines to the next section (that is, read lines until a
-section-divider or end-marker has been consumed).  Return true if
-there is such a section, false if an end-marker is seen.  Re-enable
-the most-recently-pushed boundary.
-\end{methoddesc}
-
-\begin{methoddesc}{pop}{}
-Pop a section boundary.  This boundary will no longer be interpreted
-as EOF.
-\end{methoddesc}
-
 \begin{methoddesc}{seek}{pos\optional{, whence}}
 Seek.  Seek indices are relative to the start of the current section.
 The \var{pos} and \var{whence} arguments are interpreted as for a file
@@ -93,6 +68,13 @@ seek.
 Return the file position relative to the start of the current section.
 \end{methoddesc}
 
+\begin{methoddesc}{next}{}
+Skip lines to the next section (that is, read lines until a
+section-divider or end-marker has been consumed).  Return true if
+there is such a section, false if an end-marker is seen.  Re-enable
+the most-recently-pushed boundary.
+\end{methoddesc}
+
 \begin{methoddesc}{is_data}{str}
 Return true if \var{str} is data and false if it might be a section
 boundary.  As written, it tests for a prefix other than \code{'-}\code{-'} at
@@ -104,6 +86,24 @@ boundary tests; if it always returns false it will merely slow
 processing, not cause it to fail.
 \end{methoddesc}
 
+\begin{methoddesc}{push}{str}
+Push a boundary string.  When an appropriately decorated version of
+this boundary is found as an input line, it will be interpreted as a
+section-divider or end-marker.  All subsequent
+reads will return the empty string to indicate end-of-file, until a
+call to \method{pop()} removes the boundary a or \method{next()} call
+reenables it.
+
+It is possible to push more than one boundary.  Encountering the
+most-recently-pushed boundary will return EOF; encountering any other
+boundary will raise an error.
+\end{methoddesc}
+
+\begin{methoddesc}{pop}{}
+Pop a section boundary.  This boundary will no longer be interpreted
+as EOF.
+\end{methoddesc}
+
 \begin{methoddesc}{section_divider}{str}
 Turn a boundary into a section-divider line.  By default, this
 method prepends \code{'-}\code{-'} (which MIME section boundaries have) but