Fix some bad formatting in -Zmacro-stats output.

I also double-checked that everything looks good on some real-world
crates.

Author: nnethercote

compiler/rustc_interface/src/passes.rs

@@ -371,7 +371,7 @@ fn print_macro_stats(ecx: &ExtCtxt<'_>) {
             // The name won't abut or overlap with the uses value, but it does
             // overlap with the empty part of the uses column. Shrink the width
             // of the uses column to account for the excess name length.
-            uses_w = uses_with_underscores.len() + 1
+            uses_w -= name.len() - name_w;
         };
 
         _ = writeln!(

tests/ui/stats/macro-stats.stderr

@@ -22,11 +22,11 @@ macro-stats trait_tys!                            1          2        2.0
 macro-stats n99!                                  2          2        1.0          4        2.0
 macro-stats none!                                 1          1        1.0          4        4.0
 macro-stats u32!                                  1          1        1.0          3        3.0
-macro-stats long_name_that_fits_on_one_line! 10         10        1.0          0        0.0
+macro-stats long_name_that_fits_on_one_line!     10         10        1.0          0        0.0
 macro-stats long_name_that_fits_on_one_line_____! 1          1        1.0          0        0.0
-macro-stats long_name_that_fits_on_one_line____! 1          1        1.0          0        0.0
-macro-stats long_name_that_fits_on_one_line___! 1          1        1.0          0        0.0
-macro-stats long_name_that_fits_on_one_line__! 1          1        1.0          0        0.0
-macro-stats long_name_that_fits_on_one_line_! 1          1        1.0          0        0.0
+macro-stats long_name_that_fits_on_one_line____!  1          1        1.0          0        0.0
+macro-stats long_name_that_fits_on_one_line___!   1          1        1.0          0        0.0
+macro-stats long_name_that_fits_on_one_line__!    1          1        1.0          0        0.0
+macro-stats long_name_that_fits_on_one_line_!     1          1        1.0          0        0.0
 macro-stats #[test]                               1          1        1.0          0        0.0
 macro-stats ===================================================================================