Make PROCESS private

Author: djc

src/process/mod.rs

@@ -201,7 +201,7 @@ fn clear_process() {
 }
 
 thread_local! {
-    pub(crate) static PROCESS: RefCell<Option<Process>> = const { RefCell::new(None) };
+    static PROCESS: RefCell<Option<Process>> = const { RefCell::new(None) };
 }
 
 // ----------- real process -----------------