[Relax][PyTorch] Add rnn_tanh.input converter

[cchung100m]

Hi Committers,

This PR addresses the rnn_tanh.input part of issue #18364. Any suggestions would be appreciated if you are available.

[gemini-code-assist]

Code Review

This pull request adds support for translating vanilla tanh-RNN cells (_rnn_tanh and _rnn_tanh_cell_unroll) in the TVM Relax PyTorch frontend. The review feedback identifies three critical issues: a typo in the function call premute_dims instead of permute_dims, an incorrect range definition for the reverse path iteration that lacks a step argument, and an incorrect initialization of the forward hidden state using zeros instead of slicing the input hidden state hx with take.

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