fix: updated conformance checking section, made may uppercase, small language improvement

Author: bergos

shacl12-core/index.html

@@ -1761,8 +1761,8 @@ <h4>Declaring the Severity of a Shape or Constraint</h4>
 						</tr>
 					</table>
 					<p>
-						Validation engines may treat <code>sh:Info</code> and <code>sh:Warning</code> as non-violating based on
-						options passed to the engine. By default, they must be treated as violations.
+						Validation engines MAY treat <code>sh:Info</code> and <code>sh:Warning</code> as non-violating based on
+						options passed to the engine. By default, they are treated as violations.
 					</p>
 					<p>
 						In addition to declaring severities per shape, the property <code>sh:severity</code> can also be used
@@ -2814,7 +2814,7 @@ <h4>Handling of Recursive Shapes</h4>
 				<h3>Conformance Checking</h3>
 				<p>
 					A <a>focus node</a> <dfn data-lt="conform|conformance">conforms</dfn> to a <a>shape</a> if and only if
-					the set of result of the <a>validation</a> of the <a>focus node</a> against the <a>shape</a> is empty and no <a>failure</a>
+					the set of result of the <a>validation</a> of the <a>focus node</a> against the <a>shape</a> does not contain any results with a severity level representing a violation and no <a>failure</a>
 					has been reported by it.
 				</p>
 				<p>