post rustfmt whitespace fixup (#9436)

Taking best bits of rustfmt's format_strings

Co-authored-by: Alexander Popiak <alexander.popiak@gmail.com>

substrate/primitives/npos-elections/src/balancing.rs

@@ -157,8 +157,8 @@ pub(crate) fn balance_voter<AccountId: IdentifierT>(
 	let last_stake = elected_edges
 		.get(last_index)
 		.expect(
-			"length of elected_edges is greater than or equal 2; last_index index is at \
-		the minimum elected_edges.len() - 1; index is within range; qed",
+			"length of elected_edges is greater than or equal 2; last_index index is at the \
+			 minimum elected_edges.len() - 1; index is within range; qed",
 		)
 		.candidate
 		.borrow()

substrate/primitives/runtime-interface/test-wasm-deprecated/src/lib.rs

@@ -30,8 +30,8 @@ include!(concat!(env!("OUT_DIR"), "/wasm_binary.rs"));
 #[cfg(feature = "std")]
 pub fn wasm_binary_unwrap() -> &'static [u8] {
 	WASM_BINARY.expect(
-		"Development wasm binary is not available. Testing is only \
-						supported with the flag disabled.",
+		"Development wasm binary is not available. Testing is only supported with the flag \
+		 disabled.",
 	)
 }