[Docs] Fix duplicate license headers and incorrect module paths after tirx rename

[tlopex]

• Remove duplicate Apache license blocks in docs/get_started/overview.rst and docs/README.md introduced by [Refactor] Bring up tirx namespace #18913, which render as visible garbage text in built documentation
• Fix incorrect tirx/schedule and tirx/tensor_intrin paths in docs/arch/index.rst — these modules are in s_tir/, not tirx/

[gemini-code-assist]

Code Review

This pull request cleans up redundant license headers in the documentation and updates the architecture guide to reflect the correct directory structure for schedule primitives and tensor intrinsics. A suggestion was made to improve the flow and readability of the updated section in the architecture documentation.

[gemini-code-assist]

While the information presented is now correct, the structure feels a bit disjointed. To improve readability and flow, consider rephrasing this section to better integrate the information about s_tir. Here is a suggestion that maintains the list format for clarity:

Suggested change

	Besides the IR data structures, the tirx module also includes:
	- A set of schedule primitives to control the generated code in ``tirx/schedule``.
	- A set of builtin intrinsics in ``tirx/tensor_intrin``.
	- A set of analysis passes to analyze the tirx functions in ``tirx/analysis``.
	- A set of transformation passes to lower or optimize the tirx functions in ``tirx/transform``.
	The schedule primitives and tensor intrinsics are in ``s_tir/schedule`` and ``s_tir/tensor_intrin`` respectively.
	Besides the IR data structures, the tirx module includes:
	- A set of analysis passes to analyze the tirx functions in ``tirx/analysis``.
	- A set of transformation passes to lower or optimize the tirx functions in ``tirx/transform``.
	Note that the related schedule primitives and tensor intrinsics are located in ``s_tir/schedule`` and ``s_tir/tensor_intrin`` respectively.