Fix normative language in notes (#1010)

* Fix normative language in notes

* Subjectify functions & function options

Co-authored-by: Addison Phillips <[email protected]>

* Update spec/intro.md

---------

Co-authored-by: Addison Phillips <[email protected]>

Author: eemeli

spec/intro.md

@@ -118,10 +118,10 @@ which satisfy either of the following two requirements:
 
 All other _identifiers_ in these categories are reserved for the use of implementations or users.
 
-> [!NOTE]
-> Users defining custom _identifiers_ SHOULD include at least one character outside these ranges
-> to ensure that they will be compatible with future versions of this specification.
-> They SHOULD also use the _namespace_ feature to avoid collisions with other implementations.
+> [!IMPORTANT]
+> Implementation-defined or user-defined _functions_ and _function_ _options_
+> SHOULD use a _namespace_ as part of their _identifiers_
+> to help avoid collisions with other implementations.
 
 Future versions of this specification will not introduce changes
 to the data model that would result in a data model representation

spec/syntax.md

@@ -117,7 +117,6 @@ A **_<dfn>local variable</dfn>_** is a _variable_ created as the result of a _lo
 > that use the UTF-16 encoding 
 > and do not check for unpaired surrogates.
 > (Strings in Java or JavaScript are examples of this.)
-> These code points SHOULD NOT be used in a _message_.
 > Unpaired surrogate code points are likely an indication of mistakes
 > or errors in the creation, serialization, or processing of the _message_.
 > Many processes will convert them to