Add short-with-failures to help

And make the README match the help output.

README.md

@@ -37,12 +37,11 @@ gotestsum --format short-verbose
 ```
 
 Supported formats:
- * `dots` - output one character per test.
- * `short` (default) - output a line for each test package.
- * `short-with-failures` - like short, but prints test output as soon as a test
-   fails.
- * `standard-quiet` - the default `go test` format.
- * `short-verbose` - output a line for each test and package.
+ * `dots` - print a character for each test.
+ * `short` (default) - print a line for each package.
+ * `short-with-failures` - print a line for each package and failed test output.
+ * `short-verbose` - print a line for each test and package.
+ * `standard-quiet` - the standard `go test` format.
  * `standard-verbose` - the standard `go test -v` format.
 
 Have a suggestion for some other format? Please open an issue!

main.go

@@ -65,11 +65,12 @@ Flags:
 		flags.PrintDefaults()
 		fmt.Fprint(os.Stderr, `
 Formats:
-    dots              print a character for each test
-    short             print a line for each package
-    short-verbose     print a line for each test and package
-    standard-quiet    default go test format
-    standard-verbose  default go test -v format
+    dots                print a character for each test
+    short               print a line for each package
+    short-with-failures print a line for each package and failed test output
+    short-verbose       print a line for each test and package
+    standard-quiet      standard go test format
+    standard-verbose    standard go test -v format
 `)
 	}
 	flags.BoolVar(&opts.debug, "debug", false, "enabled debug")