rustdoc-json-types Discriminant: fix typo

"when to complex" should obviously be "too complex"

Author: kraktus

src/rustdoc-json-types/lib.rs

@@ -634,7 +634,7 @@ pub struct Discriminant {
     /// hexadecimal, and underscores), making it unsuitable to be machine
     /// interpreted.
     ///
-    /// In some cases, when the value is to complex, this may be `"{ _ }"`.
+    /// In some cases, when the value is too complex, this may be `"{ _ }"`.
     /// When this occurs is unstable, and may change without notice.
     pub expr: String,
     /// The numerical value of the discriminant. Stored as a string due to