Improved wording of error messages of missing remainder implementations

Author: Matthias Kaak

core/src/ops/arith.rs

@@ -545,7 +545,7 @@ div_impl_float! { f32 f64 }
 #[lang = "rem"]
 #[stable(feature = "rust1", since = "1.0.0")]
 #[rustc_on_unimplemented(
-    message = "cannot rem `{Self}` by `{Rhs}`",
+    message = "cannot calculate the remainder of `{Self}` divided by `{Rhs}`",
     label = "no implementation for `{Self} % {Rhs}`"
 )]
 #[doc(alias = "%")]
@@ -981,7 +981,7 @@ div_assign_impl! { usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 f32 f64 }
 #[lang = "rem_assign"]
 #[stable(feature = "op_assign_traits", since = "1.8.0")]
 #[rustc_on_unimplemented(
-    message = "cannot rem-assign `{Self}` by `{Rhs}``",
+    message = "cannot calculate and assign the remainder of `{Self}` divided by `{Rhs}`",
     label = "no implementation for `{Self} %= {Rhs}`"
 )]
 #[doc(alias = "%")]