doc: document that property names are unique

Both queries and definitions only support each individual name appearing once.
It is an error to have a name appear more than once.

Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/16716)

diff --git a/doc/man7/property.pod b/doc/man7/property.pod
index a75f262246f5cce0d0e71d941b57b8ea785a4e39..109336ba47258c5acdcb08b1ac364eac13f1d560 100644 (file)
--- a/doc/man7/property.pod
+++ b/doc/man7/property.pod
@@ -41,7 +41,8 @@ property names like
 
 A I<property> is a I<name=value> pair.
 A I<property definition> is a sequence of comma separated properties.
-There can be any number of properties in a definition.
+There can be any number of properties in a definition, however each name must
+be unique.
 For example: "" defines an empty property definition (i.e., no restriction);
 "my.foo=bar" defines a property named I<my.foo> which has a string value I<bar>
 and "iteration.count=3" defines a property named I<iteration.count> which
@@ -68,6 +69,7 @@ Matching such clauses is not a requirement, but any additional optional
 match counts in favor of the algorithm.
 More details about that in the B<Lookups> section.
 A I<property query> is a sequence of comma separated property query clauses.
+It is an error if a property name appears in more than one query clause.
 The full syntax for property queries appears below, but the available syntactic
 features are: