mupdf: provide symlink mupdf -> mupdf-x11

This symlink is present on other distros and avoids confusing users on the CLI,
which are used to calling mupdf-x11 as mupdf.

pkgs/applications/misc/mupdf/default.nix

@@ -64,6 +64,7 @@ in stdenv.mkDerivation rec {
     EOF
 
     moveToOutput "bin" "$bin"
+    ln -s "$bin/bin/mupdf-x11" "$bin/bin/mupdf"
     mkdir -p $bin/share/applications
     cat > $bin/share/applications/mupdf.desktop <<EOF
     [Desktop Entry]