Keep original literal notation in suggestion

[koka831]

While I did some investigation of #9866 (I couldn't reproduce it though) I found that unused_rounding formats as follows:

3.0_f64.round() // => 3.0f64

This PR makes them preserve as the original notation.

3.0_f64.round() // => 3.0_f64

changelog: Suggestion Enhancement: [unused_rounding]: The suggestion now preserves the original float literal notation

[rust-highfive]

r? @Jarcho

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[Jarcho]

This should just grab a snippet of the receiver rather than rebuild the string.

[koka831]

Thank you for review, that's right.
fixed it in 1baa6cd .

[Jarcho]

Thank you. @bors r+

[bors]

📌 Commit 1baa6cd has been approved by Jarcho

It is now in the queue for this repository.

[bors]

⌛ Testing commit 1baa6cd with merge a85c8f3...

[bors]

☀️ Test successful - checks-action_dev_test, checks-action_remark_test, checks-action_test
Approved by: Jarcho
Pushing a85c8f3 to master...