Update spinner.adoc

Removed unneeded new line break.

src/docs/asciidoc/jme3/contributions/tonegodgui/spinner.adoc

@@ -10,7 +10,7 @@ ifdef::env-github,env-browser[:outfilesuffix: .adoc]
 
 == Spinner Class
 
-The Spinner class provides:+
+The Spinner class provides:
 
 *  A display area for the current step value
 *  An increment button