wikilinks: also remove ? and leading/trailing spaces from urls

wikilinks.lua

@@ -1,10 +1,14 @@
 -- Pandoc's wikilinks_title_after_pipe extension does basic hyperlinking
 -- of [[bracketed wiki links]]. This lua filter does the rest, mimicking
--- Obsidian's wiki linking where possible. It
+-- Obsidian's wiki linking where possible. It makes these adjustments
--- - replaces spaces with hyphens in the uri path and fragment
+-- (to both path and fragment):
--- - lower-cases the fragment
+-- - removes problem characters: ' ?
--- - adds ".html" to the path when appropriate (preserving any fragment).
+-- - then removes any leading/trailing spaces
+-- - replaces internal spaces with hyphens
+-- - lower-cases the fragment if any
+-- - adds ".html" to the path when appropriate, while preserving the fragment.
 --   This is not needed on hledger.org, but makes links work when rendered locally.
+--
 -- Current limitations: unlike Obsidian wikilinks,
 -- - these do not find files across folders - correct path is required
 -- - these are not aware of file existence - targets should exist
@@ -12,24 +16,27 @@
 
 function Link(el)
    if el.title == "wikilink" then
-      t = el.target .. "#"
+      t = el.target
+      t = t:gsub("[?']", "")
+      t = t:gsub("^ +", "")
+      t = t:gsub(" +$", "")
       t = t:gsub(" ", "-")
-      t = t:gsub("'", "")
+      t = t .. "#"
       path, frag = t:match("([^#]*)#([^#]*)")
-      t = path
+      u = path
       if not (
          path:len() == 0 or
          path:match('%.html$') or
          path:match('%.%.$') or
          path:match('/$')
       ) then
-         t = t .. ".html"
+         u = u .. ".html"
       end
       if frag:len() > 0 then
          frag = pandoc.text.lower(frag)
-         t = t .. "#" .. frag
+         u = u .. "#" .. frag
       end
-      el.target = t
+      el.target = u
    end
    return el
 end