[Feature Request]: lint rule that warns about unqualified imports

[jabraham17]

Given the possibility that a module could add a new symbol and break code, it would be nice if chplcheck could help users avoid this situation

For example

// in A.chpl
module A {
  proc bar() { }
}

// in Main.chpl
module Main {
  public use A;
  proc foo() { }
  proc main() {
    foo();
    bar();
  }
}

Should someone add a proc foo to A, this code will break. However, a linter rule for unqualified import could se use A and warn, suggesting import A.

Regardless of the code breaking argument, users may just generally prefer only using qualified access and this lint rule can help them enforce that.

Note that I strongly feel that this should be an off-by-default lint warning that users can opt into if they wish.