refactor: msg.js: use named export, remove declareLegacyNamespace (#5768)

scripts/gulpfiles/chunks.json

@@ -74,6 +74,7 @@
     "./core/menu.js",
     "./core/contextmenu.js",
     "./core/blocks.js",
+    "./core/utils/global.js",
     "./core/utils/useragent.js",
     "./core/utils/svg.js",
     "./core/utils/dom.js",
@@ -245,6 +246,7 @@
     "./core/serialization/blocks.js",
     "./core/utils/toolbox.js",
     "./core/mutator.js",
+    "./core/msg.js",
     "./core/connection_type.js",
     "./core/internal_constants.js",
     "./core/utils/colour.js",
@@ -263,8 +265,6 @@
     "./core/xml.js",
     "./core/connection.js",
     "./core/common.js",
-    "./core/utils/global.js",
-    "./core/msg.js",
     "./closure/goog/base_minimal.js",
     "./core/requires.js",
     "./blocks/variables_dynamic.js",

scripts/migration/renamings.js

@@ -910,6 +910,10 @@ const renamings = {
       export: 'MetricsManager',
       path: 'Blockly.MetricsManager',
     },
+    'Blockly.Msg': {
+      export: 'Msg',
+      path: 'Blockly.Msg',
+    },
     'Blockly.Mutator': {
       export: 'Mutator',
       path: 'Blockly.Mutator',