doc: Prevent ldoc from generating URLs with spaces.

For dubious reasons, ldoc uses the human readable name for the URLs
instead of the machine readable one. If the name has multiple words,
this causes the URLs to have spaces or %20 in them.

This commits remove all spaces from the "kinds" and then use `:gsub()`
in the template to convert underscores to spaces.

**WARNING** This breaks all URLs again. But this is necessary to prevent
broken links when the user paste them with spaces instead of %20.

docs/config.ld

@@ -100,12 +100,12 @@ sort_modules=true
 
 -- Add more project level (left side index) types.
 new_type("widgetmod"   , "Widgets"   , true)
-new_type("containermod", "Widget containers", true)
-new_type("layoutmod"   , "Widget layouts"   , true)
-new_type("coreclassmod", "Core components"  , true)
-new_type("popupmod"    , "Popups and bars"  , true)
-new_type("utillib"     , "Utility libraries", true)
-new_type("themelib"    , "Theme related libraries", true)
+new_type("containermod", "Widget_containers", true)
+new_type("layoutmod"   , "Widget_layouts"   , true)
+new_type("coreclassmod", "Core_components"  , true)
+new_type("popupmod"    , "Popups_and_bars"  , true)
+new_type("utillib"     , "Utility_libraries", true)
+new_type("themelib"    , "Theme_related_libraries", true)
 
 file = {
     -- C parts of libraries

docs/ldoc.ltp

@@ -30,6 +30,7 @@
 # local function M(txt,item) return ldoc.markup(txt,item,ldoc.plain) end
 # local nowrap = ldoc.wrap and '' or 'nowrap'
 # local html_space = function(s) return s:gsub(" ", "%%20") end
+# local no_underscores = function(s) return s:gsub("_", " ") end
 
 <!-- Menu -->
 
@@ -68,7 +69,7 @@
 # local this_mod = module and module.name
 # for kind, mods, type in ldoc.kinds() do
 #  if ldoc.allowed_in_contents(type,module) then
-<h2>$(kind)</h2>
+<h2>$(no_underscores(kind))</h2>
 <ul class="$(kind=='Topics' and '' or 'nowrap')">
 #  for mod in mods() do local name = display_name(mod)
 #   if mod.name == this_mod then