std::thread: avoid leading whitespace in some panic messages

Author: RalfJung

library/std/src/thread/current.rs

@@ -243,16 +243,16 @@ fn init_current(current: *mut ()) -> Thread {
         // a particular API should be entirely allocation-free, feel free to open
         // an issue on the Rust repository, we'll see what we can do.
         rtabort!(
-            "\n
-            Attempted to access thread-local data while allocating said data.\n
-            Do not access functions that allocate in the global allocator!\n
-            This is a bug in the global allocator.\n
+            "\n\
+            Attempted to access thread-local data while allocating said data.\n\
+            Do not access functions that allocate in the global allocator!\n\
+            This is a bug in the global allocator.\n\
         "
         )
     } else {
         debug_assert_eq!(current, DESTROYED);
         panic!(
-            "use of std::thread::current() is not possible after the thread's
+            "use of std::thread::current() is not possible after the thread's \
          local data has been destroyed"
         )
     }