Update references to Python versions and Unicode versions

Author: Rob Speer

docs/index.rst

@@ -301,8 +301,8 @@ Variants of UTF-8
 
 *ftfy.chardata* and *ftfy.build_data*: trivia about characters
 --------------------------------------------------------------
-These files load information about the character properties in Unicode 9.0.
-Yes, even if your version of Python doesn't support Unicode 9.0. This ensures
+These files load information about the character properties in Unicode 11.0.
+Yes, even if your version of Python doesn't support Unicode 11.0. This ensures
 that ftfy's behavior is consistent across versions.
 
 .. automodule:: ftfy.chardata

ftfy/build_data.py

@@ -5,7 +5,7 @@
 classes we care about change, or if a new version of Python supports a new
 Unicode standard and we want it to affect our string decoding.
 
-The file that we generate is based on Unicode 9.0, as supported by Python 3.6.
+The file that we generate is based on Unicode 11.0, as supported by Python 3.7.
 You can certainly use it in earlier versions. This simply makes sure that we
 get consistent results from running ftfy on different versions of Python.
 
@@ -39,16 +39,16 @@ def make_char_data_file(do_it_anyway=False):
     Build the compressed data file 'char_classes.dat' and write it to the
     current directory.
 
-    If you run this, run it in Python 3.6 or later. It will run in earlier
-    versions, but you won't get the Unicode 9 standard, leading to inconsistent
-    behavior.
+    If you run this, run it in Python 3.7.0 or later. It will run in earlier
+    versions, but you won't get the Unicode 11 standard, leading to inconsistent
+    behavior. Pre-releases of Python 3.7 won't work (Unicode 11 wasn't out yet).
 
     To protect against this, running this in the wrong version of Python will
     raise an error unless you pass `do_it_anyway=True`.
     """
-    if sys.hexversion < 0x03060000 and not do_it_anyway:
+    if sys.hexversion < 0x030700f0 and not do_it_anyway:
         raise RuntimeError(
-            "This function should be run in Python 3.6 or later."
+            "This function should be run in Python 3.7.0 or later."
         )
 
     cclasses = [None] * 0x110000