fix(languages): U+00A0 nbsp in French causes unexpected word breaks

languages/fr.lua

@@ -223,9 +223,13 @@ function SILE.nodeMakers.fr:iterator (items)
   local removed = 0
   for k = 1, #items do
     if self:mustRemove(k, items) then
-      removed = removed + 1
+      -- the index is actually a character position in the byte stream.
+      -- So we need to take its actual byte length into account.
+      -- For instance, U+00A0 NBSP is 2 bytes long (0xC2 0xA0) in UTF-8.
+      removed = removed + string.len(items[k].text)
     else
-      items[k].index = items[k].index - removed -- index has changed due to removals
+      -- index has changed due to removals
+      items[k].index = items[k].index - removed
       table.insert(cleanItems, items[k])
     end
   end