[php] Psalm annotate exception class props.

This tells Psalm that these are a part of an expected API.

Author: olleolleolle

php/psalm.xml

@@ -1,8 +1,8 @@
 <?xml version="1.0"?>
 <psalm
     errorLevel="1"
-    resolveFromConfigFile="false"
-    findUnusedBaselineEntry="false"
+    resolveFromConfigFile="true"
+    findUnusedBaselineEntry="true"
     findUnusedCode="true"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xmlns="https://getpsalm.org/schema/config"

php/src/ParserException/UnexpectedEofException.php

@@ -7,6 +7,9 @@
 use Cucumber\Gherkin\ParserException;
 use Cucumber\Gherkin\Token;
 
+/**
+ * @psalm-api
+ */
 final class UnexpectedEofException extends ParserException
 {
     /**

php/src/ParserException/UnexpectedTokenException.php

@@ -8,6 +8,9 @@
 use Cucumber\Gherkin\ParserException;
 use Cucumber\Gherkin\Token;
 
+/**
+ * @psalm-api
+ */
 final class UnexpectedTokenException extends ParserException
 {
     /**