Namersw (#7167)

* Define and use Namer overloads

* more

* NamespacedType needs a public string-like overload

* Move Rust FieldOffsetName to Namer LegacyRustFieldOffsetName

* Started swift

* More Namer updates

* Remove more usage of the variable 'name' which was semantically overloaded

* unshadow varible

* Make ptr to bool explicit

Co-authored-by: Casper Neo <cneo@google.com>

src/idl_gen_rust.cpp

@@ -37,6 +37,7 @@ Namer::Config RustDefaultConfig() {
            /*variables=*/Case::kUnknown,  // Unused.
            /*variants=*/Case::kKeep,
            /*enum_variant_seperator=*/"::",
+           /*escape_keywords=*/Namer::Config::Escape::BeforeConvertingCase,
            /*namespaces=*/Case::kSnake,
            /*namespace_seperator=*/"::",
            /*object_prefix=*/"",