epub: other than the missing ncx file, it now passes validation

FossilOrigin-Name: 2f66a6dd264cd2fbbf7c6dbd4d4228027899629e6a19faa61bf08d2dfd8b96f3

doc/book/general/retro-unu

@@ -39,7 +39,7 @@ As an example,
 This illustrates the format. Only code in the fenced blocks
 (between \~~~ pairs) get extracted and run.
 
-(Note: this only applies to *source files*; fences are not used
+(Note: this only applies to source files; fences are not used
 when entering code interactively).
 
 ## On The Name

example/markdown-to-xhtml.retro

@@ -152,6 +152,7 @@ to deal with.
        @Emphasis n:zero? [ '<em> &Emphasis v:on ]
                          [ '</em> &Emphasis v:off ] choose s:put ] case
   $\ [ &Escape v:on ] case
+  ASCII:SPACE [ sp ] case
   c:put<code> ;
 
 :s:put<formatted> [ format ] s:for-each ;
@@ -305,7 +306,7 @@ some older RETRO source files.
 ~~~
 :rule?
   dup [ '---- s:begins-with? ] [ '-+-+ s:begins-with? ] bi or ;
-:format:rule drop '<hr/> s:put nl ;
+:format:rule drop '<span_class="hr"></span> s:put nl ;
 ~~~
 
 *Lists*
@@ -423,3 +424,4 @@ listed at https://github.com/chriskempson/tomorrow-theme
     .h2 { font-size: 120%; }
     .h3 { font-size: 115%; }
     .h4 { font-size: 110%; }
+    .hr { display: block; height: 2px; background: #000000; }

generate-epub.retro

@@ -94,7 +94,8 @@ Spine:
 '<package_xmlns="http://www.idpf.org/2007/opf"_unique-identifier="BookID"_version="2.0"> file:s:put file:nl
 '__<metadata_xmlns:dc="http://purl.org/dc/elements/1.1/"_xmlns:opf="http://www.idpf.org/2007/opf"> file:s:put file:nl
 '____<dc:title>RETRO_Forth_:_User_Manual</dc:title> file:s:put file:nl
-'____<dc:identifier_id="BookID"_opf:scheme="CustomID">...bookid...</dc:identifier> file:s:put file:nl
+'____<dc:identifier_id="BookID"_opf:scheme="CustomID">works.forth.retro-manual</dc:identifier> file:s:put file:nl
+'____<dc:language>en</dc:language> file:s:put file:nl
 '__</metadata> file:s:put file:nl
 
 '__<manifest> file:s:put file:nl
@@ -105,10 +106,12 @@ drop
 '__<spine_toc="ncx"> file:s:put file:nl
 #0 TOC [ drop dup '____<itemref_idref="CHAP%n"_linear="yes"/> s:format file:s:put file:nl n:inc ] a:for-each drop
 '__</spine> file:s:put file:nl
+~~~
 
 '__<guide> file:s:put file:nl
 '__</guide> file:s:put file:nl
 
+~~~
 '</package> file:s:put file:nl
 @FID file:close
 ~~~
@@ -145,5 +148,6 @@ Cleanup is the final step. Remove the temporary epub directory
 
 ~~~
 'STEP:_Cleanup s:put nl
+'cp_-r_chapters_~/atua unix:system
 'rm_-rf_epub_chapters unix:system
 ~~~