Java: Added Java 15 keywords (#2567)

components/prism-java.js

@@ -1,6 +1,6 @@
 (function (Prism) {
 
-	var keywords = /\b(?:abstract|assert|boolean|break|byte|case|catch|char|class|const|continue|default|do|double|else|enum|exports|extends|final|finally|float|for|goto|if|implements|import|instanceof|int|interface|long|module|native|new|null|open|opens|package|private|protected|provides|public|record|requires|return|short|static|strictfp|super|switch|synchronized|this|throw|throws|to|transient|transitive|try|uses|var|void|volatile|while|with|yield)\b/;
+	var keywords = /\b(?:abstract|assert|boolean|break|byte|case|catch|char|class|const|continue|default|do|double|else|enum|exports|extends|final|finally|float|for|goto|if|implements|import|instanceof|int|interface|long|module|native|new|non-sealed|null|open|opens|package|permits|private|protected|provides|public|record|requires|return|sealed|short|static|strictfp|super|switch|synchronized|this|throw|throws|to|transient|transitive|try|uses|var|void|volatile|while|with|yield)\b/;
 
 	// based on the java naming conventions
 	var className = /\b[A-Z](?:\w*[a-z]\w*)?\b/;

tests/languages/java/keyword_feature.test

@@ -24,6 +24,7 @@ module requires transitive
 exports uses open
 opens with to provides
 yield
+sealed non-sealed permits
 
 ----------------------------------------------------
 
@@ -53,7 +54,8 @@ yield
 	["keyword", "module"], ["keyword", "requires"], ["keyword", "transitive"],
 	["keyword", "exports"], ["keyword", "uses"], ["keyword", "open"],
 	["keyword", "opens"], ["keyword", "with"], ["keyword", "to"], ["keyword", "provides"],
-	["keyword", "yield"]
+	["keyword", "yield"],
+	["keyword", "sealed"], ["keyword", "non-sealed"], ["keyword", "permits"]
 ]
 
 ----------------------------------------------------