Rollup merge of #106971 - oli-obk:tait_error, r=davidtwco

Handle diagnostics customization on the fluent side (for one specific diagnostic)

r? ```@davidtwco```

diff --cc compiler/rustc_borrowck/src/region_infer/opaque_types.rs
Simple merge

diff --cc compiler/rustc_error_messages/locales/en-US/infer.ftl
Simple merge