When changed, print diff info

If "fodt-gen-kw-uri-map --check-changed" detects a change, also print
information about what changed. This can be helpful for debugging.

scripts/python/src/fodt/keyword_uri_map_generator.py

@@ -154,6 +154,20 @@ def add_alias(kw_uri_map: dict[str, str], keyword: str, alias: str) -> None:
     uri = kw_uri_map[keyword]
     kw_uri_map[alias] = uri
 
+
+def display_map_diff(orig_kw_uri_map: dict[str, str], kw_uri_map: dict[str, str]) -> None:
+    # First check keys
+    for kw in sorted(orig_kw_uri_map.keys()):
+        if kw not in kw_uri_map:
+            logging.error(f"Keyword {kw} not found in new map.")
+        else:
+            if orig_kw_uri_map[kw] != kw_uri_map[kw]:
+                logging.error(f"URI for keyword {kw} has changed. Old: {orig_kw_uri_map[kw]}, New: {kw_uri_map[kw]}")
+    for kw in sorted(kw_uri_map.keys()):
+        if kw not in orig_kw_uri_map:
+            logging.error(f"Keyword {kw} not found in old map.")
+    return
+
 # fodt-gen-kw-uri-map
 # -------------------
 #
@@ -189,6 +203,7 @@ def gen_kw_uri_map_cli(maindir: str|None, keyword_dir: str|None, check_changed:
         orig_kw_uri_map = helpers.load_kw_uri_map(maindir)
         if orig_kw_uri_map != kw_uri_map:
             logging.error("Files have changed.")
+            display_map_diff(orig_kw_uri_map, kw_uri_map)
             exit(1)
         else:
             logging.info("Files have not changed.")