feat: interpret usual backslash escapes in quoted include filename

mkdocs_semiliterate/plugin.py

@@ -91,9 +91,12 @@ is checked for `{! ... !}`.
         # OK, we have found (the start of) an inclusion and must process it
         preamble = line[:include_match.start()]
         remainder = line[include_match.end(1):]
+        doublequoted = False
         body_pattern = StreamInclusion.include_quoted_file
         if include_match[2].isspace():
             body_pattern = StreamInclusion.include_bare_file
+        elif include_match[2] == '"':
+            doublequoted = True
         body_match = body_pattern.search(remainder)
         if not body_match:
             for extra_line in self.input_stream:
@@ -105,7 +108,12 @@ is checked for `{! ... !}`.
             errmsg = "semiliterate: End of file while scanning for `!}`"
             utils.log.error(errmsg)
             raise EOFError(errmsg)
-        include_path = self.include_root + '/' + body_match['fn']
+        filename = body_match['fn']
+        if doublequoted:
+            filename = (filename.encode('latin-1', 'backslashreplace')
+                                .decode('unicode-escape'))
+        include_path = self.include_root + '/' + filename
+        print(f"Including |{include_path}|")
         new_root = re.match(r'(.*)/', include_path)[1]
         try:
             include_parameters = yaml.safe_load(body_match['yml'])