rustc_mir: remove extra space when pretty-printing MIR.

Author: anyska

src/librustc_mir/util/pretty.rs

@@ -561,7 +561,7 @@ fn write_mir_sig(
 
     ty::print::with_forced_impl_filename_line(|| {
         // see notes on #41697 elsewhere
-        write!(w, " {}", tcx.def_path_str(src.def_id()))
+        write!(w, "{}", tcx.def_path_str(src.def_id()))
     })?;
 
     if src.promoted.is_none() && is_function {

src/test/mir-opt/retag.rs

@@ -114,7 +114,7 @@ fn main() {
 // }
 // END rustc.main-{{closure}}.EraseRegions.after.mir
 // START rustc.ptr-drop_in_place.Test.SimplifyCfg-make_shim.after.mir
-// fn  std::intrinsics::drop_in_place(_1: *mut Test) -> () {
+// fn std::intrinsics::drop_in_place(_1: *mut Test) -> () {
 //     ...
 //     bb0: {
 //         Retag([raw] _1);