Add support for escape characters, make nuon a JSON superset (#4706)

* WIP

* Finish adding escape support in strings

* Try to fix windows

crates/nu-command/src/conversions/into/duration.rs

@@ -226,7 +226,7 @@ mod test {
         let span = Span::test_data();
         let word = Value::test_string("1sec");
         let expected = Value::Duration {
-            val: 1 * 1000 * 1000 * 1000,
+            val: 1000 * 1000 * 1000,
             span,
         };
 

crates/nu-command/src/strings/parse.rs

@@ -48,7 +48,7 @@ impl Command for Parse {
             },
             Example {
                 description: "Parse a string using regex pattern",
-                example: "echo \"hi there\" | parse -r \"(?P<foo>\\w+) (?P<bar>\\w+)\"",
+                example: "echo \"hi there\" | parse -r '(?P<foo>\\w+) (?P<bar>\\w+)'",
                 result: Some(result),
             },
         ]