add exiftool's list of Canon tags

ui/medashare/metadata/crw.py

@@ -15,6 +15,7 @@ import struct
 # Various specifications:
 # CRW: https://web.archive.org/web/20081230095207/http://xyrion.org/ciff/CIFFspecV1R04.pdf
 # CR2: https://web.archive.org/web/20230404015346/http://lclevy.free.fr/cr2/
+# Canon Tag info: https://exiftool.org/TagNames/Canon.html
 # TIFF: https://www.loc.gov/preservation/digital/formats/fdd/fdd000022.shtml
 # TIFF: https://web.archive.org/web/20180810205359/https://www.adobe.io/content/udp/en/open/standards/TIFF/_jcr_content/contentbody/download/file.res/TIFF6.pdf
 # JPEG: https://www.w3.org/Graphics/JPEG/itu-t81.pdf