Shorten types more when only interesting part is lifetimes

[estebank]

We have a mechanims (Highlight) to change the name of inferred lifetimes in types so that we can refer to them by a number. Modify it so that it also avoids printing sub-parts of the type that are irrelevant to the situation at hand. The new behavior will print any sub part that has any lifetime (as they might be informative) instead of just the lifetimes being replaced. This was found to produce the best effect empirically in the test suite, striking a nice balance between shortening labels and being informative.

error: lifetime may not live long enough
  --> $DIR/wrong-closure-arg-suggestion-125325.rs:46:18
   |
LL |         take(|_| to_fn(|_| self.counter += 1));
   |              --- ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ returning this value requires that `'1` must outlive `'2`
   |              | |
   |              | return type of closure `aux::Map<{closure@...}>` contains a lifetime `'2`
   |              lifetime `'1` represents this closure's body
   |
   = note: closure implements `Fn`, so references to captured variables can't escape the closure

error: implementation of `FnOnce` is not general enough
  --> $DIR/higher-ranked-auto-trait-15.rs:20:5
   |
LL |     require_send(future);
   |     ^^^^^^^^^^^^^^^^^^^^ implementation of `FnOnce` is not general enough
   |
   = note: closure with signature `fn(&'0 ...) -> std::slice::Iter<'_, i32>` must implement `FnOnce<(&'1 Vec<i32>,)>`, for any two lifetimes `'0` and `'1`...
   = note: ...but it actually implements `FnOnce<(&Vec<i32>,)>`

Made this change after noticing that the first of the errors above had a corresponding .stderr file with lines longer than 150 columns by using rg ".. \| .{150}" -g *.stderr.

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[estebank]

This is not using the "highlighted expected/found" we use for E0308... It'll likely require extending that logic to also learn to replace lifetime names in the same way that Highlight does.

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