Add a command-line option providing information about tools.

- All tools have a url.
- Not deriving the url from the package database.

make-readme.py

@@ -9,8 +9,7 @@ import eris.tools as tools
 
 
 def tool_markup(tool):
-    url = tools.url_of_tool(tool)
-    return (tool.__name__ if url is None else f"[{tool.__name__}]({url})")
+    return f"[{tool.__name__}]({tool.url})"
 
 
 def main():
@@ -76,7 +75,7 @@ Extensions({len(extension_set)-1}) | Tools({len(tool_set)})
     for extensions, tools_ in all_tools:
         print("%s | %s" % (
             " ".join("." + extension for extension in extensions),
-            " • ".join(tool_markup(tool) for tool in tools_)))
+            " • ".join(f"[{tool.__name__}]({tool.url})" for tool in tools_)))
 
 
 if __name__ == "__main__":