detect gradle kotlin DSL files

convert `project-types` local variable to a custom variable for
extendability
include build.gradle.kts to detect all gradle projects
update glob patterns to watch these files

lsp-java.el

@@ -65,6 +65,11 @@ Use http://download.eclipse.org/che/che-ls-jdt/snapshots/che-jdt-language-server
  "face for activity message"
  :group 'lsp-java)
 
+(defcustom lsp-java-project-types '("pom.xml" "build.gradle" "build.gradle.kts" ".project")
+ "File names of possible project configuration files found at project root."
+ :group 'lsp-java
+ :type '(repeat file))
+
 (defcustom lsp-java-workspace-dir (expand-file-name (locate-user-emacs-file "workspace/"))
  "LSP java workspace directory."
  :group 'lsp-java
@@ -472,9 +477,8 @@ The current directory is assumed to be the java project’s root otherwise."
  ((string= default-directory lsp-java-workspace-cache-dir) default-directory)
  ((and (featurep 'projectile) (projectile-project-p)) (projectile-project-root))
  ((vc-backend default-directory) (expand-file-name (vc-root-dir)))
- (t (let ((project-types '("pom.xml" "build.gradle" ".project")))
- (or (seq-some (lambda (file) (locate-dominating-file default-directory file)) project-types)
- default-directory)))))
+ (t (or (seq-some (lambda (file) (locate-dominating-file default-directory file)) lsp-java-project-types)
+ default-directory))))
 
 (defun lsp-java--language-status-callback (workspace params)
  "Callback for client initialized.
@@ -1122,7 +1126,7 @@ PROJECT-URI uri of the item."
  ("registerOptions" (ht ("watchers"
  (vector (ht ("globPattern" "**/*.java"))
  (ht ("globPattern" "**/pom.xml"))
- (ht ("globPattern" "**/*.gradle"))
+ (ht ("globPattern" "**/*.gradle{,.kts}"))
  (ht ("globPattern" "**/.project"))
  (ht ("globPattern" "**/.classpath"))
  (ht ("globPattern" "**/settings/*.prefs"))))))))))