Update error_codes.rs

Author: Dylan-DPC

src/librustc/error_codes.rs

@@ -1912,15 +1912,17 @@ fn bar<'short, 'long>(c: Foo<'short>, l: &'long isize) {
 ```
 
 In this example, we tried to set a value with an incompatible lifetime to
-another one (`'long` != `'short`). We can solve this issue in two different
-ways: either we make `'short` lives longer than `'long`:
+another one (`'long` is unrelated to `'short`). We can solve this issue in two different
+ways:
+
+Either we make `'short` live at least as long as `'long`:
 
 ```
 struct Foo<'a> {
     x: &'a isize,
 }
 
-// we set 'short to outlive 'long
+// we set 'short to live at least as long as 'long
 fn bar<'short: 'long, 'long>(c: Foo<'short>, l: &'long isize) {
     let _: Foo<'long> = c; // ok!
 }