Fixes unused imports in Rust code generator (#8828)

* Fixes unused imports in Rust code generator

* Regenerates generated schemas

samples/rust_generated/my_game/sample/weapon_generated.rs

@@ -1,46 +1,39 @@
 // automatically generated by the FlatBuffers compiler, do not modify
 // @generated
 extern crate alloc;
-extern crate flatbuffers;
-use alloc::boxed::Box;
-use alloc::string::{String, ToString};
-use alloc::vec::Vec;
-use core::mem;
-use core::cmp::Ordering;
-use self::flatbuffers::{EndianScalar, Follow};
 use super::*;
 pub enum WeaponOffset {}
 #[derive(Copy, Clone, PartialEq)]
 
 pub struct Weapon<'a> {
-  pub _tab: flatbuffers::Table<'a>,
+  pub _tab: ::flatbuffers::Table<'a>,
 }
 
-impl<'a> flatbuffers::Follow<'a> for Weapon<'a> {
+impl<'a> ::flatbuffers::Follow<'a> for Weapon<'a> {
   type Inner = Weapon<'a>;
   #[inline]
   unsafe fn follow(buf: &'a [u8], loc: usize) -> Self::Inner {
-    Self { _tab: unsafe { flatbuffers::Table::new(buf, loc) } }
+    Self { _tab: unsafe { ::flatbuffers::Table::new(buf, loc) } }
   }
 }
 
 impl<'a> Weapon<'a> {
-  pub const VT_NAME: flatbuffers::VOffsetT = 4;
-  pub const VT_DAMAGE: flatbuffers::VOffsetT = 6;
+  pub const VT_NAME: ::flatbuffers::VOffsetT = 4;
+  pub const VT_DAMAGE: ::flatbuffers::VOffsetT = 6;
 
   pub const fn get_fully_qualified_name() -> &'static str {
     "MyGame.Sample.Weapon"
   }
 
   #[inline]
-  pub unsafe fn init_from_table(table: flatbuffers::Table<'a>) -> Self {
+  pub unsafe fn init_from_table(table: ::flatbuffers::Table<'a>) -> Self {
     Weapon { _tab: table }
   }
   #[allow(unused_mut)]
-  pub fn create<'bldr: 'args, 'args: 'mut_bldr, 'mut_bldr, A: flatbuffers::Allocator + 'bldr>(
-    _fbb: &'mut_bldr mut flatbuffers::FlatBufferBuilder<'bldr, A>,
+  pub fn create<'bldr: 'args, 'args: 'mut_bldr, 'mut_bldr, A: ::flatbuffers::Allocator + 'bldr>(
+    _fbb: &'mut_bldr mut ::flatbuffers::FlatBufferBuilder<'bldr, A>,
     args: &'args WeaponArgs<'args>
-  ) -> flatbuffers::WIPOffset<Weapon<'bldr>> {
+  ) -> ::flatbuffers::WIPOffset<Weapon<'bldr>> {
     let mut builder = WeaponBuilder::new(_fbb);
     if let Some(x) = args.name { builder.add_name(x); }
     builder.add_damage(args.damage);
@@ -49,7 +42,7 @@ impl<'a> Weapon<'a> {
 
   pub fn unpack(&self) -> WeaponT {
     let name = self.name().map(|x| {
-      x.to_string()
+      alloc::string::ToString::to_string(x)
     });
     let damage = self.damage();
     WeaponT {
@@ -63,7 +56,7 @@ impl<'a> Weapon<'a> {
     // Safety:
     // Created from valid Table for this object
     // which contains a valid value in this slot
-    unsafe { self._tab.get::<flatbuffers::ForwardsUOffset<&str>>(Weapon::VT_NAME, None)}
+    unsafe { self._tab.get::<::flatbuffers::ForwardsUOffset<&str>>(Weapon::VT_NAME, None)}
   }
   #[inline]
   pub fn damage(&self) -> i16 {
@@ -74,21 +67,20 @@ impl<'a> Weapon<'a> {
   }
 }
 
-impl flatbuffers::Verifiable for Weapon<'_> {
+impl ::flatbuffers::Verifiable for Weapon<'_> {
   #[inline]
   fn run_verifier(
-    v: &mut flatbuffers::Verifier, pos: usize
-  ) -> Result<(), flatbuffers::InvalidFlatbuffer> {
-    use self::flatbuffers::Verifiable;
+    v: &mut ::flatbuffers::Verifier, pos: usize
+  ) -> Result<(), ::flatbuffers::InvalidFlatbuffer> {
     v.visit_table(pos)?
-     .visit_field::<flatbuffers::ForwardsUOffset<&str>>("name", Self::VT_NAME, false)?
+     .visit_field::<::flatbuffers::ForwardsUOffset<&str>>("name", Self::VT_NAME, false)?
      .visit_field::<i16>("damage", Self::VT_DAMAGE, false)?
      .finish();
     Ok(())
   }
 }
 pub struct WeaponArgs<'a> {
-    pub name: Option<flatbuffers::WIPOffset<&'a str>>,
+    pub name: Option<::flatbuffers::WIPOffset<&'a str>>,
     pub damage: i16,
 }
 impl<'a> Default for WeaponArgs<'a> {
@@ -101,21 +93,21 @@ impl<'a> Default for WeaponArgs<'a> {
   }
 }
 
-pub struct WeaponBuilder<'a: 'b, 'b, A: flatbuffers::Allocator + 'a> {
-  fbb_: &'b mut flatbuffers::FlatBufferBuilder<'a, A>,
-  start_: flatbuffers::WIPOffset<flatbuffers::TableUnfinishedWIPOffset>,
+pub struct WeaponBuilder<'a: 'b, 'b, A: ::flatbuffers::Allocator + 'a> {
+  fbb_: &'b mut ::flatbuffers::FlatBufferBuilder<'a, A>,
+  start_: ::flatbuffers::WIPOffset<::flatbuffers::TableUnfinishedWIPOffset>,
 }
-impl<'a: 'b, 'b, A: flatbuffers::Allocator + 'a> WeaponBuilder<'a, 'b, A> {
+impl<'a: 'b, 'b, A: ::flatbuffers::Allocator + 'a> WeaponBuilder<'a, 'b, A> {
   #[inline]
-  pub fn add_name(&mut self, name: flatbuffers::WIPOffset<&'b  str>) {
-    self.fbb_.push_slot_always::<flatbuffers::WIPOffset<_>>(Weapon::VT_NAME, name);
+  pub fn add_name(&mut self, name: ::flatbuffers::WIPOffset<&'b  str>) {
+    self.fbb_.push_slot_always::<::flatbuffers::WIPOffset<_>>(Weapon::VT_NAME, name);
   }
   #[inline]
   pub fn add_damage(&mut self, damage: i16) {
     self.fbb_.push_slot::<i16>(Weapon::VT_DAMAGE, damage, 0);
   }
   #[inline]
-  pub fn new(_fbb: &'b mut flatbuffers::FlatBufferBuilder<'a, A>) -> WeaponBuilder<'a, 'b, A> {
+  pub fn new(_fbb: &'b mut ::flatbuffers::FlatBufferBuilder<'a, A>) -> WeaponBuilder<'a, 'b, A> {
     let start = _fbb.start_table();
     WeaponBuilder {
       fbb_: _fbb,
@@ -123,14 +115,14 @@ impl<'a: 'b, 'b, A: flatbuffers::Allocator + 'a> WeaponBuilder<'a, 'b, A> {
     }
   }
   #[inline]
-  pub fn finish(self) -> flatbuffers::WIPOffset<Weapon<'a>> {
+  pub fn finish(self) -> ::flatbuffers::WIPOffset<Weapon<'a>> {
     let o = self.fbb_.end_table(self.start_);
-    flatbuffers::WIPOffset::new(o.value())
+    ::flatbuffers::WIPOffset::new(o.value())
   }
 }
 
-impl core::fmt::Debug for Weapon<'_> {
-  fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+impl ::core::fmt::Debug for Weapon<'_> {
+  fn fmt(&self, f: &mut ::core::fmt::Formatter<'_>) -> ::core::fmt::Result {
     let mut ds = f.debug_struct("Weapon");
       ds.field("name", &self.name());
       ds.field("damage", &self.damage());
@@ -140,7 +132,7 @@ impl core::fmt::Debug for Weapon<'_> {
 #[non_exhaustive]
 #[derive(Debug, Clone, PartialEq)]
 pub struct WeaponT {
-  pub name: Option<String>,
+  pub name: Option<alloc::string::String>,
   pub damage: i16,
 }
 impl Default for WeaponT {
@@ -152,10 +144,10 @@ impl Default for WeaponT {
   }
 }
 impl WeaponT {
-  pub fn pack<'b, A: flatbuffers::Allocator + 'b>(
+  pub fn pack<'b, A: ::flatbuffers::Allocator + 'b>(
     &self,
-    _fbb: &mut flatbuffers::FlatBufferBuilder<'b, A>
-  ) -> flatbuffers::WIPOffset<Weapon<'b>> {
+    _fbb: &mut ::flatbuffers::FlatBufferBuilder<'b, A>
+  ) -> ::flatbuffers::WIPOffset<Weapon<'b>> {
     let name = self.name.as_ref().map(|x|{
       _fbb.create_string(x)
     });