Remove use of deprecated std::collections::Bound

Author: bstrie

crates/proc_macro_srv/src/rustc_server.rs

@@ -10,9 +10,10 @@
 
 use crate::proc_macro::bridge::{self, server};
 
-use std::collections::{Bound, HashMap};
+use std::collections::HashMap;
 use std::hash::Hash;
 use std::iter::FromIterator;
+use std::ops::Bound;
 use std::str::FromStr;
 use std::{ascii, vec::IntoIter};