Revert "Use Fx* variants of HashMap and HashSet everywhere in Zed" (#7492)

Reverts zed-industries/zed#7481

This would regress performance because we'd be using the standard
library's hash maps everywhere, so reverting for now.

crates/util/Cargo.toml

@@ -15,7 +15,6 @@ test-support = ["tempfile", "git2"]
 [dependencies]
 anyhow.workspace = true
 backtrace = "0.3"
-collections.workspace = true
 dirs = "3.0"
 futures.workspace = true
 git2 = { workspace = true, optional = true }

crates/util/src/test/marked_text.rs

@@ -1,5 +1,4 @@
-use collections::HashMap;
-use std::{cmp::Ordering, ops::Range};
+use std::{cmp::Ordering, collections::HashMap, ops::Range};
 
 /// Construct a string and a list of offsets within that string using a single
 /// string containing embedded position markers.