Reorganization of the WASM bindings.cc template

* Move all bindings into a single EMSCRIPTEN_BINDINGS block
* Move all auto generated bindings line to the start of the block
* Alphabetically sort the constants binding lines

PiperOrigin-RevId: 837142009
Change-Id: I218a37dbc0ca6c6f16a455718889c08fe1b41d56

wasm/codegen/tests/generators_test.py

@@ -801,17 +801,14 @@ class EnumsGeneratorTest(absltest.TestCase):
   def test_generate_enum_bindings(self):
 
     expected_code = """
-EMSCRIPTEN_BINDINGS(mujoco_enums) {
-  enum_<AnotherEnum>("AnotherEnum")
-    .value("ALPHA", ALPHA)
-    .value("BETA", BETA);
-
-  enum_<TestEnum>("TestEnum")
-    .value("FIRST_VAL", FIRST_VAL)
-    .value("SECOND_VAL", SECOND_VAL)
-    .value("THIRD_VAL", THIRD_VAL);
-
-}""".strip()
+enum_<AnotherEnum>("AnotherEnum")
+  .value("ALPHA", ALPHA)
+  .value("BETA", BETA);
+enum_<TestEnum>("TestEnum")
+  .value("FIRST_VAL", FIRST_VAL)
+  .value("SECOND_VAL", SECOND_VAL)
+  .value("THIRD_VAL", THIRD_VAL);
+""".strip()
 
     markers_and_content = enums.generate([
         ast_nodes.EnumDecl(