doc: Fix log_parameter_max_length docs to reference log_min_duration_statement

doc: Fix log_parameter_max_length docs to reference log_min_duration_statement

The documentation for log_parameter_max_length said it affects messages
generated by log_duration. However, log_duration alone does not log bind
parameter values, so this is misleading.

This commit updates the documentation to reference log_min_duration_statement,
which can log bind parameters, to better reflect actual behavior.

Backpatch to all supported versions.

Author: Fujii Masao <masao.fujii@gmail.com>
Reviewed-by: Surya Poondla <suryapoondla4@gmail.com>
Discussion: https://postgr.es/m/CAHGQGwGnCVMVz8-LU9F8Sh57bkQX3jMZzx7age7M0LFEz5=Fog@mail.gmail.com
Backpatch-through: 14