Scope of phone validation

[karladler]

Question / Bug
Is the isMobilePhone function intended to only validate mobile phone numbers or should it actually also be possible for landlines? If yes, I would rewrite this as a bug, since some german landline numbers would not validate.

Examples
+4935178686876

Suggestion

• Phone validation is in general a well discussed topic and really hard to do. Covering all countries and edge cases would also increase the package size a lot. It might be good, for the sake of this module, to completely outsource it to external packages like awesome-phonenumber. Tree shaking should do the rest.

[WikiRik]

It should only validate mobile phone numbers, but I know that there is some improvement to be done on that front. See also #2124

Outsourcing has not been discussed recently as far as I know