[SUGGESTION] insert() expression like delete()

[jpmateo022]

Hi,

First of all, I really loved this library. I've been using this on my project to easily construct and parse queries. Not sure if this is the right area to post this but when I'm looking for an expression method for insert() similar to delete() and update(), It seems that it's missing.

I would like to suggest if you can add an insert() query similar to delete in expressions.
https://github.com/tobymao/sqlglot/blob/main/sqlglot/expressions.py#L4698

Thank you!

[georgesittas]

Created a PR for this: #1630