Fix settings inheritance

This looks correct now.
A new document will start with a default config that includes e.g.
the "pages" directory to be "pages". So this is in its base config,
not in its own config - but it still is relative to its own config.

Author: dannyadair

src/pdfbaker/config.py

@@ -63,15 +63,14 @@ def __init__(
             "dist",
         ):
             if directory in config.get("directories", {}):
-                # Set in this config file
+                # Set in this config file, relative to this config file
                 directories[directory] = self.resolve_path(
                     config["directories"][directory]
                 )
             elif directory in base_config.get("directories", {}):
-                # Inherited or not yet relevant/mentioned
+                # Inherited (absolute) or default (relative to _this_ config)
                 directories[directory] = self.resolve_path(
-                    str(base_config["directories"][directory]),
-                    directory=base_config["directories"]["config"],
+                    str(base_config["directories"][directory])
                 )
         super().__init__(deep_merge(base_config, config))
         self["directories"] = directories