container: improve documentation

This change removes inconsistencies collected over time in this package.

Signed-off-by: Ophestra <cat@gensokyo.uk>

container/errors.go

@@ -43,7 +43,8 @@ func messageFromError(err error) (m string, ok bool) {
 }
 
 // messagePrefix checks and prefixes the error message of a non-pointer error.
-// While this is usable for pointer errors, such use should be avoided as nil check is omitted.
+// While this is usable for pointer errors, such use should be avoided as nil
+// check is omitted.
 func messagePrefix[T error](prefix string, err error) (string, bool) {
 	var targetError T
 	if errors.As(err, &targetError) {