Canonicalise filenames in accordance with Unicode 9.0.0

Testing suggests that MediaWiki on Commons uses the casing table from
Unicode 8.0.0 or 9.0.0 for capitalising the first letters of page
titles.  Thus when Usage Bot capitalises the first letter of a title,
it should not apply case mappings that were introduced in later
versions of Unicode.

I've dealt with this by adding a list of the characters that have
gained case mappings in later Unicode versions, which is a bit ugly
but is the best I can think of.

Thanks to Ivanbranco for reporting the problem.

usage_bot/util.py

@@ -2,6 +2,39 @@
 from subprocess import run, CalledProcessError, PIPE
 from urllib.parse import unquote
 
+# MediaWiki seems to use a casing table from Unicode 8.0.0 or 9.0.0.
+# These are the characters that gained a Simple_Uppercase_Mapping
+# between Unicode 9.0.0 and Unicode 15.0.0.  For compatibility with
+# MediaWiki, we shouldn't up-case these characters at the start of
+# filenames.
+suppress_casing = {
+    "\U00000282", "\U000010D0", "\U000010D1", "\U000010D2", "\U000010D3",
+    "\U000010D4", "\U000010D5", "\U000010D6", "\U000010D7", "\U000010D8",
+    "\U000010D9", "\U000010DA", "\U000010DB", "\U000010DC", "\U000010DD",
+    "\U000010DE", "\U000010DF", "\U000010E0", "\U000010E1", "\U000010E2",
+    "\U000010E3", "\U000010E4", "\U000010E5", "\U000010E6", "\U000010E7",
+    "\U000010E8", "\U000010E9", "\U000010EA", "\U000010EB", "\U000010EC",
+    "\U000010ED", "\U000010EE", "\U000010EF", "\U000010F0", "\U000010F1",
+    "\U000010F2", "\U000010F3", "\U000010F4", "\U000010F5", "\U000010F6",
+    "\U000010F7", "\U000010F8", "\U000010F9", "\U000010FA", "\U000010FD",
+    "\U000010FE", "\U000010FF", "\U00001D8E", "\U00002C5F", "\U0000A794",
+    "\U0000A7B9", "\U0000A7BB", "\U0000A7BD", "\U0000A7BF", "\U0000A7C1",
+    "\U0000A7C3", "\U0000A7C8", "\U0000A7CA", "\U0000A7D1", "\U0000A7D7",
+    "\U0000A7D9", "\U0000A7F6", "\U00010597", "\U00010598", "\U00010599",
+    "\U0001059A", "\U0001059B", "\U0001059C", "\U0001059D", "\U0001059E",
+    "\U0001059F", "\U000105A0", "\U000105A1", "\U000105A3", "\U000105A4",
+    "\U000105A5", "\U000105A6", "\U000105A7", "\U000105A8", "\U000105A9",
+    "\U000105AA", "\U000105AB", "\U000105AC", "\U000105AD", "\U000105AE",
+    "\U000105AF", "\U000105B0", "\U000105B1", "\U000105B3", "\U000105B4",
+    "\U000105B5", "\U000105B6", "\U000105B7", "\U000105B8", "\U000105B9",
+    "\U000105BB", "\U000105BC", "\U00016E60", "\U00016E61", "\U00016E62",
+    "\U00016E63", "\U00016E64", "\U00016E65", "\U00016E66", "\U00016E67",
+    "\U00016E68", "\U00016E69", "\U00016E6A", "\U00016E6B", "\U00016E6C",
+    "\U00016E6D", "\U00016E6E", "\U00016E6F", "\U00016E70", "\U00016E71",
+    "\U00016E72", "\U00016E73", "\U00016E74", "\U00016E75", "\U00016E76",
+    "\U00016E77", "\U00016E78", "\U00016E79", "\U00016E7A", "\U00016E7B",
+    "\U00016E7C", "\U00016E7D", "\U00016E7E", "\U00016E7F"}
+
 def canonicalise_name(name):
     # Produce the canonical form of a name for use in galleries and as
     # a key.  Broadly equivalent to part of the splitTitleString
@@ -15,7 +48,7 @@ def canonicalise_name(name):
     name = name.strip(" ")
     # Galleries don't need the namespace prefix, so we strip it off.
     name = re.sub(r"^File: *", "", name, flags=re.IGNORECASE)
-    if len(name) > 0:
+    if len(name) > 0 and name[0] not in suppress_casing:
         # This is not the proper way to capitalise a string, since it
         # messes up characters with a titlecase form.  It seems to
         # match what MediaWiki does, though.