feat: lemmas for HashMap.alter and .modify

[datokrat]

This PR adds lemmas about HashMap.alter and .modify. These lemmas describe the interaction of alter and modify with the read methods of the HashMap. The additions affect the HashMap, the DHashMap and their respective raw versions. Moreover, the raw versions of alter and modify are defined.

[leanprover-community-bot]

Mathlib CI status (docs):

• ✅ Mathlib branch lean-pr-testing-6620 has successfully built against this PR. (2025-01-16 11:04:50) View Log
• ✅ Mathlib branch lean-pr-testing-6620 has successfully built against this PR. (2025-01-17 15:25:22) View Log
• ❗ Batteries/Mathlib CI will not be attempted unless your PR branches off the nightly-with-mathlib branch. Try git rebase 1d03cd6a6b9e2cab387692f5ec0d0013b9a9867d --onto 74bd40d34d1a969da65007939960c2fefd461f08. (2025-01-20 12:17:49)
• ❗ Batteries/Mathlib CI will not be attempted unless your PR branches off the nightly-with-mathlib branch. Try git rebase 1d03cd6a6b9e2cab387692f5ec0d0013b9a9867d --onto ac6a29ee834ba7fd30e9372e51493d7741e9c657. (2025-01-21 10:36:21)
• ❗ Batteries/Mathlib CI will not be attempted unless your PR branches off the nightly-with-mathlib branch. Try git rebase 35697973771b8dbbbb6b3872a40cc604764d36ae --onto f9e904af5022a57adb6105cda65d1569449346c2. (2025-01-21 12:36:39)

[datokrat]

@TwoFX The DHashMap lemmas are done now. Note that there are still some out-commented lemmas in case I happen to need them when I proceed. Next I'll do Raw and HashMap. (Keeping the MyRawLemmas file for now to speed up compilation during development)