docs(pangram): improve approach's content and links

Author: princemuel

exercises/practice/pangram/.approaches/set-len/content.md

@@ -8,11 +8,12 @@ def is_pangram(sentence):
 - This approach first makes a [set][set] from the [`lower`][lower]cased characters of the `sentence`.
 - The characters are filtered using a [set comprehension][set-comprehension] with an `if` [`isalpha()`][isalpha] statement, so that only alphabetic characters make it into the set.
 - The function returns whether the [`len()`][len] of the [`set`][set] is `26`.
-  If the number of unique ASCII letters in the `set` is equal to the `26` letters in the ASCII alphabet, then the function will return `True`.
+  If the number of unique [ASCII][ascii] (American Standard Code for Information Interchange) letters in the `set` is equal to the `26` letters in the [ASCII][ascii] alphabet, then the function will return `True`.
 - This approach is efficient because it uses a set to eliminate duplicates and directly checks the length, which is a constant time operation.
 
 [lower]: https://docs.python.org/3/library/stdtypes.html?#str.lower
 [set]: https://docs.python.org/3/library/stdtypes.html?#set
 [set-comprehension]: https://realpython.com/python-set-comprehension/#introducing-set-comprehensions
 [isalpha]: https://docs.python.org/3/library/stdtypes.html?highlight=isalpha#str.isalpha
 [len]: https://docs.python.org/3/library/functions.html?#len
+[ascii]: https://en.wikipedia.org/wiki/ASCII