Escape the unmatched surrogates with lower-case hexadecimal numbers

tbu- · tbu- · commit bb6c27e74d08 · 2016-07-29T00:52:03.000+02:00
It's done the same way for the rest of the codepoint escapes.
diff --git a/src/libstd/sys/common/wtf8.rs b/src/libstd/sys/common/wtf8.rs
@@ -408,7 +408,7 @@ impl fmt::Debug for Wtf8 {
                             &self.bytes[pos .. surrogate_pos]
                         )},
                     )?;
-                    write!(formatter, "\\u{{{:X}}}", surrogate)?;
+                    write!(formatter, "\\u{{{:x}}}", surrogate)?;
                     pos = surrogate_pos + 3;
                 }
             }
@@ -1066,7 +1066,7 @@ mod tests {
     fn wtf8buf_show() {
         let mut string = Wtf8Buf::from_str("a\té \u{7f}💩\r");
         string.push(CodePoint::from_u32(0xD800).unwrap());
-        assert_eq!(format!("{:?}", string), "\"a\\té \\u{7f}\u{1f4a9}\\r\\u{D800}\"");
+        assert_eq!(format!("{:?}", string), "\"a\\té \\u{7f}\u{1f4a9}\\r\\u{d800}\"");
     }
 
     #[test]

Original file line number	Diff line number	Diff line change
`@@ -408,7 +408,7 @@ impl fmt::Debug for Wtf8 {`
`408`	`408`	`&self.bytes[pos .. surrogate_pos]`
`409`	`409`	`)},`
`410`	`410`	`)?;`
`411`		`- write!(formatter, "\\u{{{:X}}}", surrogate)?;`
	`411`	`+ write!(formatter, "\\u{{{:x}}}", surrogate)?;`
`412`	`412`	`pos = surrogate_pos + 3;`
`413`	`413`	`}`
`414`	`414`	`}`
`@@ -1066,7 +1066,7 @@ mod tests {`
`1066`	`1066`	`fn wtf8buf_show() {`
`1067`	`1067`	`let mut string = Wtf8Buf::from_str("a\té \u{7f}💩\r");`
`1068`	`1068`	`string.push(CodePoint::from_u32(0xD800).unwrap());`
`1069`		`- assert_eq!(format!("{:?}", string), "\"a\\té \\u{7f}\u{1f4a9}\\r\\u{D800}\"");`
	`1069`	`+ assert_eq!(format!("{:?}", string), "\"a\\té \\u{7f}\u{1f4a9}\\r\\u{d800}\"");`
`1070`	`1070`	`}`
`1071`	`1071`
`1072`	`1072`	`#[test]`