Complete impl parameter usage examples

[jschnelder]

Adds a missing example showing how to use TDisplay trait directly.

The documentation already shows calling .display() as a method, but doesn't demonstrate the trait usage pattern TDisplay::display(value).

[reviewable-StarkWare]

This change is 

[orizi]

Reviewable status: 0 of 1 files reviewed, 1 unresolved discussion (waiting on @jschnelder)

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docs/reference/src/components/cairo/modules/language_constructs/pages/method-calls.adoc line 33 at r1 (raw file):

fn bar<T: impl TDisplay: Display<T>>(value: T) {
    let a = TDisplay::display(value);

how is this more complete? close PR.

[orizi]

No response.

Closing.