update JSON string encodings in author directory

The following characters are no longer encoded
and are represented as themselves:

- & is no longer encoded
- / is no longer encoded
- < is no longer encoded
- > is no longer encoded
- [\x80-\xff] is no longer encoded

The author ID JSON files under `/author` have
been updated accordingly.

author/Immanuel_Herrmann.json

@@ -7,7 +7,7 @@
     "location_code" : null,
     "location_name" : null,
     "email" : null,
-    "url" : "https:\/\/web.archive.org\/web\/20071018081145\/http:\/\/pcpool.mathematik.uni-freiburg.de\/~immi\/",
+    "url" : "https://web.archive.org/web/20071018081145/http://pcpool.mathematik.uni-freiburg.de/~immi/",
     "alt_url" : null,
     "deprecated_twitter_handle" : null,
     "mastodon" : null,