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/project/src/git_store/branch_diff.rs

@@ -14,6 +14,7 @@ use gpui::{
 use language::Buffer;
 use text::BufferId;
 use util::ResultExt;
+use ztracing::instrument;
 
 use crate::{
     Project,
@@ -254,6 +255,7 @@ impl BranchDiff {
         self.repo.as_ref()
     }
 
+    #[instrument(skip_all)]
     pub fn load_buffers(&mut self, cx: &mut Context<Self>) -> Vec<DiffBuffer> {
         let mut output = Vec::default();
         let Some(repo) = self.repo.clone() else {
@@ -318,6 +320,7 @@ impl BranchDiff {
         output
     }
 
+    #[instrument(skip_all)]
     fn load_buffer(
         branch_diff: Option<git::status::TreeDiffStatus>,
         project_path: crate::ProjectPath,