Fix rust beta doc macro complaints.

Author: arik-so

lightning-invoice/src/lib.rs

@@ -795,7 +795,7 @@ impl SignedRawInvoice {
 /// variant. If no element was found `None` gets returned.
 ///
 /// The following example would extract the first B.
-/// ```
+/// ``
 /// use Enum::*;
 ///
 /// enum Enum {
@@ -806,7 +806,7 @@ impl SignedRawInvoice {
 /// let elements = vec![A(1), A(2), B(3), A(4)];
 ///
 /// assert_eq!(find_extract!(elements.iter(), Enum::B(ref x), x), Some(3u16));
-/// ```
+/// ``
 macro_rules! find_extract {
 	($iter:expr, $enm:pat, $enm_var:ident) => {
 		find_all_extract!($iter, $enm, $enm_var).next()
@@ -817,7 +817,7 @@ macro_rules! find_extract {
 /// variant through an iterator.
 ///
 /// The following example would extract all A.
-/// ```
+/// ``
 /// use Enum::*;
 ///
 /// enum Enum {
@@ -831,7 +831,7 @@ macro_rules! find_extract {
 /// 	find_all_extract!(elements.iter(), Enum::A(ref x), x).collect::<Vec<u8>>(),
 /// 	vec![1u8, 2u8, 4u8]
 /// );
-/// ```
+/// ``
 macro_rules! find_all_extract {
 	($iter:expr, $enm:pat, $enm_var:ident) => {
 		$iter.filter_map(|tf| match *tf {