ESQL: String functions ASCII

[pfcoperez]

Description

Add a function that escape characters that can not be represented with ASCII characters.

Part of #98545

[elasticsearchmachine]

Pinging @elastic/es-analytical-engine (Team:Analytics)

[nik9000]

Add a function that escape characters that can not be represented with ASCII characters.

Oh! Is that what that function is supposed to do! I never look. I just saw it in the list and moved on. Sounds useful. Maybe it should have another name? I'm not sure. If that's the traditional name I can get behind that