fix(derive): Reduce amount of deprecation noise

The main thing that might slip through is `bool`.  We'll see if we an
re-introduce that.

clap_derive/src/derives/args.rs

@@ -136,6 +136,7 @@ pub fn gen_from_arg_matches_for_struct(
             }
 
             fn from_arg_matches_mut(__clap_arg_matches: &mut clap::ArgMatches) -> ::std::result::Result<Self, clap::Error> {
+                #[allow(deprecated)]  // Assuming any deprecation in here will be related to a deprecation in `Args`
                 let v = #struct_name #constructor;
                 ::std::result::Result::Ok(v)
             }
@@ -145,6 +146,7 @@ pub fn gen_from_arg_matches_for_struct(
             }
 
             fn update_from_arg_matches_mut(&mut self, __clap_arg_matches: &mut clap::ArgMatches) -> ::std::result::Result<(), clap::Error> {
+                #[allow(deprecated)]  // Assuming any deprecation in here will be related to a deprecation in `Args`
                 #updater
                 ::std::result::Result::Ok(())
             }

clap_derive/src/derives/subcommand.rs

@@ -542,6 +542,8 @@ fn gen_from_arg_matches(
 
     quote! {
         fn from_arg_matches_mut(__clap_arg_matches: &mut clap::ArgMatches) -> ::std::result::Result<Self, clap::Error> {
+            #[allow(deprecated)]  // Assuming any deprecation in here will be related to a deprecation in `Subcommand`
+
             #( #child_subcommands )else*
 
             if let Some((#subcommand_name_var, mut __clap_arg_sub_matches)) = __clap_arg_matches.remove_subcommand() {
@@ -657,6 +659,8 @@ fn gen_update_from_arg_matches(
             &mut self,
             __clap_arg_matches: &mut clap::ArgMatches,
         ) -> ::std::result::Result<(), clap::Error> {
+            #[allow(deprecated)]  // Assuming any deprecation in here will be related to a deprecation in `Subcommand`
+
             if let Some(__clap_name) = __clap_arg_matches.subcommand_name() {
                 match self {
                     #( #subcommands ),*