doc/meref.me.in: Fix content nit and clarify.

Margin register values do not depend on the selected font (family).  In
fact they don't depend on anything.  They're always vees reckoned
against a vertical spacing of 120% of a 10 point type size.  You can't
override this with command-line register settings.  You can only change
them after the package initializes.

Clarify that vertical spacing is reset by paragraph macros (e.g., `lp`
-> `@p` -> `sz`); introduce that concept and the new `tv` register much
earlier accordingly.

1 files changed, 13 insertions, 14 deletions

diff --git a/doc/meref.me.in b/doc/meref.me.in
index 6a1baae9e..6cd9f6ac5 100644
--- a/doc/meref.me.in
+++ b/doc/meref.me.in
@@ -243,7 +243,13 @@ the type size
 to
 .NR (pp
 [10p],
-and vertical space of
+and vertical spacing
+(text baseline distance)
+to
+.NR (tv
+[120]%
+of the type size.
+Vertical space of
 .NR (ps
 [0.35v]
 is inserted
@@ -572,10 +578,9 @@ or more than eight spaces total.
 .pp
 The spacing
 of headers and footers
-is controlled by four registers,
-computing distances based on the output device's default font,
-type size,
-and vertical spacing.
+is controlled by four registers
+initialized to values scaled
+with respect to the default type size and vertical spacing.
 .NR (hm
 [4v]
 is the distance from the top of the page
@@ -696,19 +701,13 @@ by an extra
 [same as
 .NR (ps ]
 of vertical space
-and use a
-vertical spacing
-(distance between text baselines)
-as a percentage of the type size
-of
+and use a vertical spacing of
 .NR (dv
 [120].
 Long quotation pre- and post-space is stored in a dedicated register,
 while centered blocks have none;
-both use the vertical spacing register for
-normal text,
-.NR (tv
-[120].
+both use the vertical spacing of normal text,
+.NR (tv .
 .TL
 .b .(l
 .i A