Fix documentation errors in PR #82 review comments

[Copilot]

Addresses 4 documentation inaccuracies identified in PR #82 review.

Changes

• docs/test_coverage.md: Corrected KECCAK256 status from "Broken" to "Tested" - implementation is working with proper memory-based hashing
• crates/jet_runtime/src/exec.rs: Fixed Word type documentation from big-endian to little-endian (matches actual implementation using from_le_bytes)
• docs/process/new-runtime-function.md: Corrected stack helper function name from __stack_pop_1 to stack_pop_1 (no leading underscores in actual API)

All changes are documentation-only corrections aligned with existing implementation and test coverage.

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[semanticdiff-com]

Review changes with  

Changed Files

File	Status
crates/jet_runtime/src/exec.rs	0% smaller
docs/process/new-runtime-function.md	Unsupported file format
docs/test_coverage.md	Unsupported file format

[Copilot]

Pull request overview

This PR corrects four documentation inaccuracies identified during the review of PR #82. All changes align the documentation with the actual implementation and test coverage status. The changes are purely documentation fixes with no code modifications.

Changes:

• Updated KECCAK256 status from "Broken" to "Tested" in test coverage documentation
• Fixed Word type endianness documentation from big-endian to little-endian
• Corrected stack helper function name from __stack_pop_1 to stack_pop_1 in process documentation

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
docs/test_coverage.md	Updated KECCAK256 status to reflect working implementation with test coverage (lines 22, 59)
crates/jet_runtime/src/exec.rs	Corrected Word type documentation to specify little-endian storage (line 11)
docs/process/new-runtime-function.md	Fixed stack helper function name to match actual API without leading underscores (line 118)