move extended info for E0569 to numerical-order location in file
move extended info for E0569 to numerical-order location in file

We want the error explanations to appear in numerical order so that
they're easy to find. (Also, any other order would be arbitrary and thus
not constitute a Schelling point.) Bizarrely, the extended information
for E0569 was placed between E0244 and E0318 in
librustc_typeck/diagnostics.rs (when the code was introduced in
9a649c32). This commit moves it to be between E0562 and E0570, where it
belongs.

(Also, at reviewer request, say "Erroneous code example", the standard
verbiage that it has been decided that we say everywhere.)

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