[m-rev.] diff: Move a module import declaration.

[Peter Wang]

For some reason, the compiler warned about the map module being unused
in the interface section of term_subst.m when building in the
csharp and java grades, but not the C grades. I have not investigated.

---

library/term_subst.m:
    Move a module import declaration from the interface section,
    where it was unused, to the implementation section.

diff --git a/library/term_subst.m b/library/term_subst.m
index c9771149f..1165e5c07 100644
--- a/library/term_subst.m
+++ b/library/term_subst.m
@@ -20,7 +20,6 @@
 :- interface.
 
 :- import_module list.
-:- import_module map.
 :- import_module term.
 
 %---------------------------------------------------------------------------%
@@ -212,6 +211,7 @@
 
 :- implementation.
 
+:- import_module map.
 :- import_module require.
 :- import_module term_context.
 
-- 
2.37.1