avoid multi-alias line that isn't 1.48 compatible

Author: spacejam

src/tree.rs

@@ -100,7 +100,9 @@ fn bounds_error() -> Result<()> {
 /// # Ok(()) }
 /// ```
 #[derive(Clone)]
-#[doc(alias("keyspace", "bucket", "table"))]
+#[doc(alias = "keyspace")]
+#[doc(alias = "bucket")]
+#[doc(alias = "table")]
 pub struct Tree(pub(crate) Arc<TreeInner>);
 
 #[allow(clippy::module_name_repetitions)]
@@ -544,7 +546,8 @@ impl Tree {
     /// assert_eq!(db.remove(&[1]), Ok(None));
     /// # Ok(()) }
     /// ```
-    #[doc(alias("delete", "del"))]
+    #[doc(alias = "delete")]
+    #[doc(alias = "del")]
     pub fn remove<K: AsRef<[u8]>>(&self, key: K) -> Result<Option<IVec>> {
         let mut guard = pin();
         let _cc = concurrency_control::read();
@@ -610,7 +613,10 @@ impl Tree {
     /// # Ok(()) }
     /// ```
     #[allow(clippy::needless_pass_by_value)]
-    #[doc(alias("cas", "tas", "test_and_set", "test_and_swap", "compare_and_set"))]
+    #[doc(alias = "cas")]
+    #[doc(alias = "tas")]
+    #[doc(alias = "test_and_swap")]
+    #[doc(alias = "compare_and_set")]
     pub fn compare_and_swap<K, OV, NV>(
         &self,
         key: K,