PRESUBMIT: Align expected and actual guard names for easier mistake spotting.

Right now they are not aligned and since guard names are typically long,
aligning them *might* be helpful to some.

Example:
Header using the wrong include guard name FOOBARX_H_
  foobar.h:1

***************
Expected: u'FOOBAR_H_'
Found: u'FOOBARX_H_'
***************

With the CL:
***************
Expected: u'FOOBAR_H_'
Found:    u'FOOBARX_H_'
***************

Bug: None
Change-Id: I4c51b602a8da3bcb2db405def2d6193519cdea87
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1836001
Reviewed-by: Daniel Cheng <[email protected]>
Commit-Queue: Daniel Cheng <[email protected]>
Cr-Commit-Position: refs/heads/master@{#702651}
diff --git a/PRESUBMIT.py b/PRESUBMIT.py
index 5fb6c76..3d842f06 100644
--- a/PRESUBMIT.py
+++ b/PRESUBMIT.py
@@ -4374,7 +4374,7 @@
               errors.append(output_api.PresubmitPromptWarning(
                 'Header using the wrong include guard name %s' % guard_name,
                 ['%s:%d' % (f.LocalPath(), line_number + 1)],
-                'Expected: %r\nFound: %r' % (expected_guard, guard_name)))
+                'Expected: %r\nFound:    %r' % (expected_guard, guard_name)))
       else:
         # The line after #ifndef should have a #define of the same name.
         if line_number == guard_line_number + 1: