feat: TargetRpc no longer need Target prefix (#2085)

Instead of doing
```cs
[TargetRpc]
public void TargetPepe() {}
```

You can now do
```cs
[TargetRpc]
public void Pepe() {}
```

We actually tried to remove them a while ago. The way the weaver worked
back then caused an infinite recursion.

Since the Command rewrite that allows virtuals, this is no longer
a problem.  So we can drop this requirement.

Co-authored-by: Paul Pacheco <paul.pacheco@aa.com>

Assets/Mirror/Editor/Weaver/Processors/TargetRpcProcessor.cs

@@ -140,12 +140,6 @@ public static MethodDefinition ProcessTargetRpcCall(TypeDefinition td, MethodDef
 
         public static bool ProcessMethodsValidateTargetRpc(MethodDefinition md)
         {
-            if (!md.Name.StartsWith("Target"))
-            {
-                Weaver.Error($"{md.Name} must start with Target.  Consider renaming it to Target{md.Name}", md);
-                return false;
-            }
-
             if (md.IsStatic)
             {
                 Weaver.Error($"{md.Name} must not be static", md);

Assets/Mirror/Tests/Editor/TargetRpcTest.cs

@@ -8,7 +8,7 @@ class TargetRpcBehaviour : NetworkBehaviour
         public event Action<int> onSendInt;
 
         [TargetRpc]
-        public void TargetSendInt(int someInt)
+        public void SendInt(int someInt)
         {
             onSendInt?.Invoke(someInt);
         }
@@ -29,7 +29,7 @@ public void RpcIsCalled()
                 callCount++;
                 Assert.That(incomingInt, Is.EqualTo(someInt));
             };
-            hostBehaviour.TargetSendInt(someInt);
+            hostBehaviour.SendInt(someInt);
             ProcessMessages();
             Assert.That(callCount, Is.EqualTo(1));
         }

Assets/Mirror/Tests/Editor/Weaver/WeaverTargetRpcTests.cs

@@ -10,13 +10,6 @@ public void TargetRpcValid()
             Assert.That(weaverErrors, Is.Empty);
         }
 
-        [Test]
-        public void ErrorWhenMethodDoesNotStartWithTarget()
-        {
-            Assert.That(weaverErrors, Contains.Item("DoesntStartWithTarget must start with Target.  Consider renaming it to TargetDoesntStartWithTarget " +
-                "(at System.Void WeaverTargetRpcTests.ErrorWhenMethodDoesNotStartWithTarget.ErrorWhenMethodDoesNotStartWithTarget::DoesntStartWithTarget(Mirror.NetworkConnection))"));
-        }
-
         [Test]
         public void ErrorWhenTargetRpcIsStatic()
         {