added terse note about JSON-LD vis-a-vis RDF

lots of people seem confused about this and don't know that JSON-LD is generalized RDF

docs/eml-semantic-annotations-primer.md

@@ -33,7 +33,7 @@ A *triple* is composed of three parts: a **subject**, a **predicate (object prop
 
 These components are analogous to parts of a sentence: the **subject** and **object** can be thought of as nouns in the sentence and the **predicate** (object property or data property)is akin to a verb or relationship that connects the **subject** and **object**. The semantic triple expresses a statement about the associated resource, that is generally the **subject**. 
 
-There are (perhaps unfortunately) several other ways that the components of an RDF statement are sometimes described.  One popular "synonymy" for *subject-predicate-object* is *resource-property-value*, i.e. the subject is referred to as the *resource*, the predicate a *property*, and the object a *value*.  This can be confusing, since the usual definition of a *resource* is any identifiable 'thing'  object, especially one assigned a URI, and by this definition, *resources* can and often do occur in all three components of a triple.  But thinking of a triple as a *resource-property-value* does provide an indication of the directionality of the semantics of an RDF statement.
+There are (perhaps unfortunately) several other ways that the components of an RDF statement are sometimes described.  One popular "synonymy" for **subject-predicate-object** is **resource-property-value**, i.e. the subject is referred to as the **resource**, the predicate a **property**, and the object a **value**.  This can be confusing, since the usual definition of a *resource* is any identifiable 'thing' or object, especially one assigned a URI; and by this definition, *resources* can and often do occur in all three components of a triple.  But thinking of a triple as a *resource-property-value* does provide an indication of the directionality of the semantics of an RDF statement.  This latter terminology is also somewhat similar to how analogous components are named in JSON-LD.  Note that JSON-LD is closely compatible with RDF, and one format can often be readily translated to the other (although there are some exceptions).
 
 Semantic annotations added to an EML document can be extracted and processed into a semantic web format, such as RDF/XML, such that the semantic statement(s), i.e. RDF triples, become interpretable by any machines that can process the W3C standard of RDF. Those RDF statements contribute to the Semantic Web.