ADD - InvalidSymbolName to migrate symbol-name({}) error to new diagnostics infraestructure

ADD - dependencies needed to port a module to new Diagnostics infra (rustc_macros, rustc_errors, errors file, and fluent file)

compiler/rustc_error_messages/src/lib.rs

@@ -52,6 +52,7 @@ fluent_messages! {
     ty_utils => "../locales/en-US/ty_utils.ftl",
     typeck => "../locales/en-US/typeck.ftl",
     mir_dataflow => "../locales/en-US/mir_dataflow.ftl",
+    symbol_mangling => "../locales/en-US/symbol_mangling.ftl",
 }
 
 pub use fluent_generated::{self as fluent, DEFAULT_LOCALE_RESOURCES};