Try more possible asciidoc paths for qute://help fallback

doc/changelog.asciidoc

@@ -60,6 +60,8 @@ Fixed
 
 - Error when passing a substring with spaces to `:tab-take`.
 - Greasemonkey scripts which start with an UTF-8 BOM are now handled correctly.
+- When no documentation has been generated, the plaintext documentation now can
+  be shown for more files such as `qute://help/userscripts.html`.
 
 Removed
 ~~~~~~~

qutebrowser/browser/qutescheme.py

@@ -375,13 +375,20 @@ def qute_help(url):
     except OSError:
         # No .html around, let's see if we find the asciidoc
         asciidoc_path = path.replace('.html', '.asciidoc')
+        asciidoc_paths = [asciidoc_path]
         if asciidoc_path.startswith('html/doc/'):
-            asciidoc_path = asciidoc_path.replace('html/doc/', '../doc/help/')
+            asciidoc_paths += [asciidoc_path.replace('html/doc/', '../doc/help/'),
+                               asciidoc_path.replace('html/doc/', '../doc/')]
 
-        try:
+        asciidoc = None
-            asciidoc = utils.read_file(asciidoc_path)
+
-        except OSError:
+        for path in asciidoc_paths:
-            asciidoc = None
+            try:
+                asciidoc = utils.read_file(path)
+            except OSError:
+                pass
+            else:
+                break
 
         if asciidoc is None:
             raise