[SPARK-58219][PYTHON][DOC] Add More See Also sections to PySpark functions

### What changes were proposed in this pull request?

Adds reciprocal `See Also` sections to related PySpark SQL built-in function docstrings:

- Null and NaN predicates: `isnan`, `isnull`, and `isnotnull`
- Null-handling functions: `nvl` and `nvl2`
- SQL pattern and regular-expression matching functions: `like`, `ilike`, `rlike`, `regexp`, and `regexp_like`
- Array helpers: every `array_*` function now links to the closest related array or collection APIs, including search, mutation, set operations, ordering, sizing, construction, and joining
- Trigonometric functions: direct and inverse pairs, reciprocal functions, hyperbolic and inverse-hyperbolic pairs, angle conversions, and the `atan2`/`hypot` polar-coordinate pair
- Window functions: ranking and distribution functions (`row_number`, `rank`, `dense_rank`, `percent_rank`, `cume_dist`, and `ntile`), plus value-selection functions (`nth_value`, `first_value`, and `last_value`)

### Why are the changes needed?

Related functions and aliases are spread across the generated PySpark API reference. Cross-references make their different matching, null-handling, array-processing, mathematical, and windowing semantics easier to discover and compare.

### Does this PR introduce _any_ user-facing change?

No.

### How was this patch tested?

No tests were added because this changes only API docstrings. Verified each diff with `git diff --check` and parsed the module to confirm the targeted `array_*`, trigonometric, and window APIs have `See Also` sections.

### Was this patch authored or co-authored using generative AI tooling?

Generated-by: Codex (GPT-5)

Closes #57374 from zhengruifeng/python-see-also-docs.

Authored-by: Ruifeng Zheng <ruifengz@apache.org>
Signed-off-by: Ruifeng Zheng <ruifengz@apache.org>

Author: zhengruifeng