[`unused_enumerate_index`]: trigger on method calls

The lint used to check for patterns looking like:
```rs
for (_, x) in some_iter.enumerate() {
    // Index is ignored
}
```

This commit further checks for chained method calls constructs where we
can detect that the index is unused. Currently, this checks only for the
following patterns:
```rs
some_iter.enumerate().map_function(|(_, x)| ..)
let x = some_iter.enumerate();
x.map_function(|(_, x)| ..)
```
where `map_function` is one of `all`, `any`, `filter_map`, `find_map`,
`flat_map`, `for_each` or `map`.

Fixes #12411.

0 files changed, 0 insertions, 0 deletions