Add IXMLExtension doSave and ResourceToDeploy documentation

Signed-off-by: Ryan Zegray <ryan.zegray@ibm.com>

org.eclipse.lemminx/src/main/java/org/eclipse/lemminx/services/extensions/IXMLExtension.java

@@ -42,6 +42,13 @@ public interface IXMLExtension {
 	 */
 	void stop(XMLExtensionsRegistry registry);
 
+	/**
+	 * Called when the Settings or a Document have been saved. 
+	 * context.getType() can be used to determine what type was saved.
+	 * doSave is called on extension start up with a settings context to 
+	 * provide the xml settings to the extension.
+	 * @param context 
+	 */
 	default void doSave(ISaveContext context) {
 
 	}

org.eclipse.lemminx/src/main/java/org/eclipse/lemminx/uriresolver/CacheResourcesManager.java

@@ -60,26 +60,51 @@ class ResourceInfo {
 
 	}
 
+	/**
+	 * Classpath resource to deploy into the lemminx cache
+	 */
 	public static class ResourceToDeploy {
 
 		private final Path resourceCachePath;
 		private final String resourceFromClasspath;
 
+		/**
+		 * @param resourceURI           - used to compute the path to deploy the
+		 *                              resource to in the lemminx cache. Generally this
+		 *                              is the URL to the resource. Ex.
+		 *                              https://www.w3.org/2007/schema-for-xslt20.xsd
+		 * @param resourceFromClasspath - the classpath location of the resource to
+		 *                              deploy to the lemminx cache
+		 */
 		public ResourceToDeploy(String resourceURI, String resourceFromClasspath) {
 			this(URI.create(resourceURI), resourceFromClasspath);
 		}
 
+		/**
+		 * @param resourceURI           - used to compute the path to deploy the
+		 *                              resource to in the lemminx cache. Generally this
+		 *                              is the URL to the resource. Ex.
+		 *                              https://www.w3.org/2007/schema-for-xslt20.xsd
+		 * @param resourceFromClasspath - the classpath location of the resource to
+		 *                              deploy to the lemminx cache
+		 */
 		public ResourceToDeploy(URI resourceURI, String resourceFromClasspath) {
 			this.resourceCachePath = Paths.get(CACHE_PATH, resourceURI.getScheme(), resourceURI.getHost(),
 					resourceURI.getPath());
 			this.resourceFromClasspath = resourceFromClasspath.startsWith("/") ? resourceFromClasspath
 					: "/" + resourceFromClasspath;
 		}
 
+		/**
+		 * @return The computed path in the lemmix cache that the resource will be stored at
+		 */
 		public Path getDeployedPath() throws IOException {
 			return FilesUtils.getDeployedPath(resourceCachePath);
 		}
 
+		/**
+		 * @return The path to the resource on the classpath
+		 */
 		public String getResourceFromClasspath() {
 			return resourceFromClasspath;
 		}