Does \hspace need a vertical extent?

[Thomas Morgan]

Given the following input, the height of the brackets does not match
the height of the enclosed text.

  \version "2.13.2"
  \markup {
    \bracket {
      \concat {
        \hspace #1
        FOO
        \hspace #1
      }
    }
  }

This is because \hspace has a vertical extent.  I'm assuming that
this vertical extent is unnecessary; if so, the problem can be solved
by this trivial patch:

diff --git a/scm/define-markup-commands.scm b/scm/define-markup-commands.scm
index 8c057c6..c2eb778 100644
--- a/scm/define-markup-commands.scm
+++ b/scm/define-markup-commands.scm
@@ -398,8 +398,8 @@ Create an invisible object taking up horizontal space
@var{amount}.
 }
 @end lilypond"
   (if (> amount 0)
-      (ly:make-stencil "" (cons 0 amount) '(-1 . 1))
-      (ly:make-stencil "" (cons amount amount) '(-1 . 1))))
+      (ly:make-stencil "" (cons 0 amount) '(0 . 0))
+      (ly:make-stencil "" (cons amount amount) '(0 . 0))))
 
 
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