Auto merge of #4027 - kraai:remove-approx_constant-known-problems, r=phansch
Auto merge of #4027 - kraai:remove-approx_constant-known-problems, r=phansch

Remove approx_constant known problems

Fixes #4025.

changelog: Remove `approx_constant`'s documentation's "Known problems" section.

graydon/rust,aidancully/rust,graydon/rust,aidancully/rust,graydon/rust,graydon/rust,graydon/rust,aidancully/rust,graydon/rust,aidancully/rust,aidancully/rust,aidancully/rust