Slightly more verbose

Author: benjie

spec/Section 3 -- Type System.md

@@ -818,9 +818,9 @@ of rules must be adhered to by every Object type in a GraphQL schema.
          characters {"__"} (two underscores).
       2. The argument must accept a type where {IsInputType(argumentType)}
          returns {true}.
-      3. If specified, {defaultValue} must be compatible with {argumentType} as
-         per the coercion rules for that type, and coercion of {defaultValue}
-         must not cause an infinite loop.
+      3. If the argument has a default value, {defaultValue} must be compatible
+         with {argumentType} as per the coercion rules for that type, and
+         coercion of {defaultValue} must not cause an infinite loop.
 3. An object type may declare that it implements one or more unique interfaces.
 4. An object type must be a super-set of all interfaces it implements:
    1. Let this object type be {objectType}.
@@ -1530,9 +1530,9 @@ Literal Value            | Variables               | Coerced Value
       characters {"__"} (two underscores).
    3. The input field must accept a type where {IsInputType(inputFieldType)}
       returns {true}.
-   4. If specified, {defaultValue} must be compatible with {inputFieldType} as
-      per the coercion rules for that type, and coercion of {defaultValue} must
-      not cause an infinite loop.
+   4. If the input field has a default value, {defaultValue} must be compatible
+      with {inputFieldType} as per the coercion rules for that type, and
+      coercion of {defaultValue} must not cause an infinite loop.
 
 
 ### Input Object Extensions