Document that expand-file-name collapses multiple slashes. (Bug#7617)

 fileio.c (Fexpand_file_name): Doc fix.

src/ChangeLog

+2010-12-12  Eli Zaretskii  <eliz@gnu.org>
+
+	* fileio.c (Fexpand_file_name): Doc fix.  (Bug#7617)
+
 2010-12-11  Eli Zaretskii  <eliz@gnu.org>
 	* w32fns.c (Fx_show_tip): Call try_window with last argument

src/fileio.c

@@ -832,6 +832,9 @@ File name components that are `.' are removed, and
 so are file name components followed by `..', along with the `..' itself;
 note that these simplifications are done without checking the resulting
 file names in the file system.
+Multiple consecutive slashes are collapsed into a single slash,
+except at the beginning of the file name when they are significant (e.g.,
+UNC file names on MS-Windows.)
 An initial `~/' expands to your home directory.
 An initial `~USER/' expands to USER's home directory.
 See also the function `substitute-in-file-name'.
@@ -839,7 +842,7 @@ See also the function `substitute-in-file-name'.
 For technical reasons, this function can return correct but
 non-intuitive results for the root directory; for instance,
 \(expand-file-name ".." "/") returns "/..".  For this reason, use
-(directory-file-name (file-name-directory dirname)) to traverse a
+\(directory-file-name (file-name-directory dirname)) to traverse a
 filesystem tree, not (expand-file-name ".."  dirname).  */)
      (name, default_directory)
      Lisp_Object name, default_directory;