Auto merge of #130389 - Luv-Ray:LLVMMDNodeInContext2, r=nikic

llvm: replace some deprecated functions

`LLVMMDStringInContext` and `LLVMMDNodeInContext` are deprecated, replace them with `LLVMMDStringInContext2` and `LLVMMDNodeInContext2`.
Also replace `Value` with `Metadata` in some function signatures for better consistency.

compiler/rustc_codegen_gcc/src/context.rs

@@ -414,6 +414,7 @@ impl<'gcc, 'tcx> CodegenCx<'gcc, 'tcx> {
 
 impl<'gcc, 'tcx> BackendTypes for CodegenCx<'gcc, 'tcx> {
     type Value = RValue<'gcc>;
+    type Metadata = RValue<'gcc>;
     type Function = RValue<'gcc>;
 
     type BasicBlock = Block<'gcc>;