incorrect exception hint when import alias contains a dot

[cyberthirst]

Version Information

• vyper Version (output of vyper --version): c02d2d8

What's your issue about?

the hint constructed at

vyper/vyper/semantics/analysis/module.py

Lines 750 to 754 in c02d2d8

	if "." in alias:
	msg = "import requires an accompanying `as` statement"
	suggested_alias = node.name[node.name.rfind(".") :]
	hint = f"try `import {node.name} as {suggested_alias}`"
	raise StructureException(msg, node, hint=hint)

incorrectly contains .

# main.vy
import import_test.foo

throws:

vyper.exceptions.StructureException: import requires an accompanying `as` statement

  contract "tests/custom/main.vy:1", line 1:0 
  ---> 1 import import_test.foo
  -------^

  (hint: try `import import_test.foo as .foo`)

How can it be fixed?

• off by one in the index

[cyberthirst]

depends on: #4229

will push a fix once we merge