text spanners syntax on manual, update request

[José Luis Cruz]

Hi Graham,

It's necessary to change 2 lines on manual section 8.1.3 "Text
spanners" from the lilypond code paragraph.

========== START

    c1
    \textSpannerDown
-     \override TextSpanner #'edge-text = #'("rall " . "")
+    \override TextSpanner #'bound-details #'left #'text = \markup {
\upright "rall" }
    c2\startTextSpan b c\stopTextSpan a
    \break
    \textSpannerUp
-     \override TextSpanner #'edge-text = #(cons (markup #:italic "rit" ) "")
+    \override TextSpanner #'bound-details #'left #'text = \markup {
\italic "rit" }
    c2\startTextSpan b c\stopTextSpan a

============== END

(I'm using a semi-patch syntax here, where the "-" sign means removal
of the line and "+" to include the line. If there is another way you
prefer for reporting this things, please tell)


cheers,