Update entry for 'number sign'

[daobrien]

https://stylepedia.net/style/5.0/#punc-names

The entry for the number sign (#) needs to be expanded to allow for its use in (e.g.), "hash function" (see SHA-1), and probably also for the extended use covered in IBM.

[julian-cable]

@daobrien The current table entry reflects the guidance in the IBM Style "Punctuation and symbols" topic: https://www.ibm.com/docs/en/ibm-style?topic=punctuation-symbols

Do you want an entry added to the Usage Dictionary, to reflect the IBM Style "number sign" entry in Word Usage?

[daobrien]

Whatever seems appropriate? Not a hill to die on; just want to make sure that we allow for the multiple uses.

[julian-cable]

@daobrien I've added a proposed Usage Dictionary entry for "number sign".