schema parsers CHANGE warn about include in YANG 1.1 submodules

YANG 1.1 requires all submodules to be present inside main module.
Having includes in submodules is not necessary since the submodules can
reference all submodules included in the main module.
diff --git a/src/parser_yang.c b/src/parser_yang.c
index 9fe7386..591aaa5 100644
--- a/src/parser_yang.c
+++ b/src/parser_yang.c
@@ -4328,6 +4328,10 @@
 
         /* linkage */
         case LY_STMT_INCLUDE:
+            if (submod->version == LYS_VERSION_1_1) {
+                LOGWRN(PARSER_CTX(ctx), "YANG version 1.1 expects all includes in main module, includes in submodules (%s) are not necessary.",
+                        submod->name);
+            }
             LY_CHECK_RET(parse_include(ctx, submod->name, &submod->includes));
             break;
         case LY_STMT_IMPORT: