Rework intro

Signed-off-by: Etienne Millon <[email protected]>

doc/reference/foreign-archives.rst

@@ -1,10 +1,14 @@
 Foreign Archives
 ----------------
 
-You can also specify archives of separately compiled foreign object files
-that need to be packaged with an OCaml library or linked into an OCaml
-executable. To do that, use the ``foreign_archives`` field of the
-corresponding ``library`` or ``executable`` stanza. For example:
+Foreign archives are a way to link archives that are separately compiled.
+
+They are particularly useful when embedding a library written in a foreign
+language and/or built with another build system. See :ref:`foreign-sandboxing`
+for more details.
+
+To use this feature, use the ``foreign_archives`` field of the corresponding
+``library`` or ``executable`` stanza. For example:
 
 .. code:: dune
 
@@ -43,7 +47,3 @@ to the same archive name from multiple OCaml libraries and executables, so a
 foreign archive is a bit like a foreign library, hence the name of the stanza.
 The ``enabled_if`` field has the same meaning as in the :doc:`dune/library`
 stanza.
-
-Foreign archives are particularly useful when embedding a library written in
-a foreign language and/or built with another build system. See
-:ref:`foreign-sandboxing` for more details.