Enhancement: add a warning for possibly unintended pointer overload calls (e.g. calling `foo(int*)` instead of `foo(int)`)

The warning could have prevented the bug fixed in https://github.com/llvm/llvm-project/pull/165056.

This is a proposal for a new diagnostic that could detect possibly unintended calls to pointer overloads when a value overload also exists.

Consider the following code:

```
void foo(int);
void foo(int*);

void test() {
int x = 123;
int *p = &x;

foo(p); // probably intended: foo(*p);
}
```

This code is valid and unambiguous. However, in some situations, this pattern reflects a common user mistake: the programmer meant to dereference the pointer but forgot the `*`.

No source files, tests, or entry points are named. Start by reading the example and the linked pull request that motivated the proposal, then identify the compiler diagnostic area involved. Done means agreeing on the conditions for detecting this valid-but-possibly-unintended overload call and adding a warning with suitable diagnostic coverage.

Written by the indexing model from the issue text.