[temp.class.spec] Fix typo "the primary" -> "the primary template".

Author: zygoloid

source/templates.tex

@@ -3018,7 +3018,7 @@
 template<typename T> struct X<T*> { };  // \#1
 template<C T> struct X<T> { };          // \#2
 \end{codeblock}
-Both partial specializations are more specialized than the primary.
+Both partial specializations are more specialized than the primary template.
 \#1 is more specialized because the deduction of its template arguments
 from the template argument list of the class template specialization succeeds,
 while the reverse does not.