Clarify that options and attributes are unordered (#751)

* Clarify that options and attributes are unordered

* Apply suggestions from code review

Author: eemeli

spec/formatting.md

@@ -319,7 +319,7 @@ the following steps are taken:
 
 #### Option Resolution
 
-The result of resolving _option_ values is a mapping of string identifiers to values.
+The result of resolving _option_ values is an unordered mapping of string identifiers to values.
 
 For each _option_:
 

spec/syntax.md

@@ -571,6 +571,8 @@ and from each other by whitespace.
 Each _option_'s _identifier_ MUST be unique within the _annotation_:
 an _annotation_ with duplicate _option_ _identifiers_ is not valid.
 
+The order of _options_ is not significant.
+
 ```abnf
 option = identifier [s] "=" [s] (literal / variable)
 ```
@@ -772,6 +774,9 @@ The _value_ of an _attribute_ can be either a _literal_ or a _variable_.
 Multiple _attributes_ are permitted in an _expression_ or _markup_.
 Each _attribute_ is separated by whitespace.
 
+The order of _attributes_ is not significant.
+
+
 ```abnf
 attribute = "@" identifier [[s] "=" [s] (literal / variable)]
 ```