fix(transmute_ptr_to_ptr): add parens if transmute is receiver of a projection

[ada4a]

Fixes #15003

changelog: [transmute_ptr_to_ptr]: add parens if transmute is receiver of a projection

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[ada4a]

This really applies to all the transmute lints that suggest as, doesn't it...

[samueltardieu]

This really applies to all the transmute lints that suggest as, doesn't it...

More than that even. I think we should have, at some point, something like:

• a function which, given an HirId checks whether inserting something in place of this node might need to be parenthesized (even better if it returns an associativity level)
• a function which, given a suggestion, checks whether it might need to get parentheses (even better if it returns an associativity level)
• a function which, given an HirId and a suggestion, returns an updated suggestion with added parentheses if this is necessary