context CHANGE rename ly_ctx_module_implement() to lys_set_implemented()

Backward compatibility with libyang 1.x, the new name also better fits to
the functionality.
diff --git a/src/tree_schema_helpers.c b/src/tree_schema_helpers.c
index 1cc11c2..c6c4511 100644
--- a/src/tree_schema_helpers.c
+++ b/src/tree_schema_helpers.c
@@ -92,7 +92,7 @@
         }
         if (implement && !mod->implemented) {
             /* make the module implemented */
-            ly_ctx_module_implement_internal(ctx->ctx, (struct lys_module*)mod, 2);
+            lys_set_implemented_internal((struct lys_module*)mod, 2);
         }
         if (context_node && context_node->nodetype == LYS_ACTION) {
             /* move through input/output manually */