docs: efl_vpath: separate summary line from rest of description

We use the summary line in various places where such a big block of text looks
ugly. In general we handle it a bit like our commit messages. One line summary
which should stand alone with more details and explanantions following after a
empty line.

src/lib/efl/interfaces/efl_vpath.eo

@@ -1,6 +1,7 @@
 interface Efl.Vpath
 {
    [[ VPath is the EFL "Virtual Path" system that maps paths and downloads
+
      You can provide virtual paths common in unix shells like:
        "~/file.jpg"
        "~username/file.png"