adds tracing for instrumenting non-async functions (#44147)

Tracing code is not included in normal release builds
Documents how to use them in our performance docs
Only the maps and cursors are instrumented atm

# Compile times:
current main: fresh release build (cargo clean then build --release)
377.34 secs
current main: fresh debug build (cargo clean then build )
89.31 secs

tracing tracy: fresh release build (cargo clean then build --release)
374.84 secs
tracing tracy: fresh debug build (cargo clean then build )
88.95 secs

tracing tracy: fresh release build with timings (cargo clean then build
--release --features tracing)
375.77 secs
tracing tracy: fresh debug build with timings (cargo clean then build
--features tracing)
90.03 secs


Release Notes:

- N/A

---------

Co-authored-by: localcc <work@localcc.cc>

crates/git_ui/src/project_diff.rs

@@ -46,6 +46,7 @@ use workspace::{
     notifications::NotifyTaskExt,
     searchable::SearchableItemHandle,
 };
+use ztracing::instrument;
 
 actions!(
     git,
@@ -469,6 +470,7 @@ impl ProjectDiff {
         }
     }
 
+    #[instrument(skip_all)]
     fn register_buffer(
         &mut self,
         path_key: PathKey,