Simplify generation of printable representation

[SultanOrazbayev]

Using .isprintable() method to improve the readability of the function (the intent of the verification becomes clearer) and to reduce the explicit unicodedata import.

[karpathy]

are we sure these are equivalent

[SultanOrazbayev]

They are not equivalent, but using the suggested approach also resolves special cases of U+2028 and U+2029 and other space separators listed here that are not captured by the current approach (checking if the category starts with "C").

So, the current approach will capture all the categories that start with C, which according to table 12 here are in the "Other" category (last line of the table).

str.isprintable will:

Return True if all characters in the string are printable or the string is empty, False otherwise. Nonprintable characters are those characters defined in the Unicode character database as “Other” or “Separator”, excepting the ASCII space (0x20) which is considered printable. (Note that printable characters in this context are those which should not be escaped when [repr()](https://docs.python.org/3/library/functions.html#repr) is invoked on a string. It has no bearing on the handling of strings written to [sys.stdout](https://docs.python.org/3/library/sys.html#sys.stdout) or [sys.stderr](https://docs.python.org/3/library/sys.html#sys.stderr).)

So the isprintable method captures also the special cases of line and paragraph separators, U+2028 and U+2029. They are tricky in the sense that they would show up as spaces during standard python printing (so from user perspective they are not distinct from a typical space between words):

from unicodedata import category

# https://www.compart.com/en/unicode/category/Zs
for char in [u"\u2028", u"\u2029", u"\u1680"]:
    print(f"{ord(char):#04x}: {char}")
    print(f"{char.isprintable()=}") # is not printable, so would be escaped with unicode
    print(f'{category(char)}') # does not start with C, so would be included as-is
    print()

0x2028: 

char.isprintable()=False
Zl

0x2029: 

char.isprintable()=False
Zp

0x1680:  
char.isprintable()=False
Zs