Use a dedicated function for wrapper struct names

This change introduces a `wrapper_struct_name` function in `structs.py` to consistently generate the name of the C++ wrapper struct from a C struct name. All call sites in `functions.py` and `structs.py` that previously used `common.capitalize` for this purpose now call `wrapper_struct_name`.

PiperOrigin-RevId: 837544242
Change-Id: Ibe5fea8294283dae63bb8d064fd8beb8cfd3f2fe

wasm/codegen/generators/enums.py

@@ -14,15 +14,13 @@
 
 """Generates Embind bindings for MuJoCo enums."""
 
-from typing import List
-
 from introspect import ast_nodes
 
 from wasm.codegen.generators import code_builder
 
 
 def generate(
-    enums: List[ast_nodes.EnumDecl],
+    enums: list[ast_nodes.EnumDecl],
 ) -> list[tuple[str, list[str]]]:
   """Generates all Embind code for the provided enums."""