Fix some typos (#4018)

Signed-off-by: hongkuang <liurenhong@outlook.com>

substrate/frame/support/src/traits/tokens/fungible/mod.rs

@@ -20,7 +20,7 @@
 //! Also see the [`frame_tokens`] reference docs for more information about the place of
 //! `fungible` traits in Substrate.
 //!
-//! # Avaliable Traits
+//! # Available Traits
 //! - [`Inspect`]: Regular balance inspector functions.
 //! - [`Unbalanced`]: Low-level balance mutating functions. Does not guarantee proper book-keeping
 //!   and so should not be called into directly from application code. Other traits depend on this

substrate/frame/treasury/src/lib.rs

@@ -1123,7 +1123,7 @@ impl<T: Config<I>, I: 'static> OnUnbalanced<NegativeImbalanceOf<T, I>> for Palle
 	}
 }
 
-/// TypedGet implementaion to get the AccountId of the Treasury.
+/// TypedGet implementation to get the AccountId of the Treasury.
 pub struct TreasuryAccountId<R>(PhantomData<R>);
 impl<R> sp_runtime::traits::TypedGet for TreasuryAccountId<R>
 where