[Docs] Fix outdated code examples, typos, and missing API reference in documentation(2)

[tlopex]

This PR is a follow-up of #18965

• Fix incorrect variable names in Relax dataflow code example (lv0 → lv, b → n) in
  docs/deep_dive/relax/learning.rst
• Fix func.time_evaluator(func.entry_name, ...) to func.time_evaluator("add_one", ...)
  in docs/how_to/tutorials/cross_compilation_and_rpc.py, since entry_name is a class
  constant "main" but the compiled function is named "add_one"
• Fix typo tvfm.testing → tvm.testing in
  docs/how_to/dev/pytest_target_parametrization.rst
• Add missing tvm.relax.frontend.tflite automodule entry to
  docs/reference/api/python/relax/frontend.rst

[gemini-code-assist]

Code Review

This pull request improves documentation by fixing variable names and typos, adding the TFLite frontend to the Relax API reference, and updating a tutorial to use a specific function name. Feedback suggests defining a constant for the function name in the tutorial to enhance maintainability and avoid potential inconsistencies.

[gemini-code-assist]

While this change correctly fixes the issue, hardcoding the function name "add_one" as a string literal makes the code less maintainable. This name is also used on line 108 when creating the IRModule. It would be better to define a constant for the function name (e.g., ADD_ONE_FUNC_NAME = "add_one") and use it in both places. This would prevent potential inconsistencies if the function name is changed in the future.