Fix PL macro indentation when the entry spans a page break. (Note to anyone

who thinks these should be upgraded to keep an entry on a single page: look
at the footnote code in the original nroff docs, the tmac.n display code,
and then use ev 2 anyway - as long as there are no footnotes on a page with
PL, you might get away with it.)

doc/Guidebook.mn

@@ -15,22 +15,24 @@
 .\" .PE
 .\"	clean up
 .de PS
-.nr PX \\w'\\$1'u
+.nr PY \\w'\\$1\ -\ 'u			\" width of label plus " - " for line 1
-.nr PY \\w'\\$1\ -\ 'u
+.sn \\n(pdu				\" tmac.n: inter-paragraph space
-.sn \\n(pdu
+.in +\\n(PYu				\" additional indent past label (etc)
-.in +\\n(PYu
+.si					\" tmac.n: start indented section
-.si
 ..
 .\" labeled paragraph label (and first line)
 .de PL
-.ti -\\n(PYu
+.br
-\\$1\\h'|\\n(PXu'\ -\ \\c
+\\h'|-\\n(PYu'\\$1\ -\ \\c		\" back up, output the label,
+.					\" then output the " - " and attach
+.					\" the next line (the text) without
+.					\" stopping(\c: nroff section 4.2)
 ..
 .\"labeled paragraph end
 .de PE
-.ei
+.ei					\" tmac.n: end indented section
-.in -\\n(PYu
+.in -\\n(PYu				\" undo indent past label (etc)
-.sn \\n(pdu
+.sn \\n(pdu				\" tmac.n: inter-paragraph space
 ..
 .\" end of labeled paragrah
 .mt