hello app copyedits (#23)

[SC-238693](https://app.shortcut.com/launchdarkly/story/238693/quickstart-copyedits-for-sdk-installation-instructions)

minor edits to align with spec

Author: louis-launchdarkly

README.md

@@ -1,4 +1,4 @@
-# LaunchDarkly Sample Java Application
+# LaunchDarkly sample Java application
 
 We've built a simple console application that demonstrates how LaunchDarkly's SDK works.
 
@@ -20,4 +20,4 @@ This project uses [Gradle](https://gradle.org/). It requires that Java is alread
 
 2. On the command line, run `./gradlew run` (or, on Windows, `gradlew run`).
 
-You should see the message `"Feature flag '<flag key>' is <true/false> for this context"`.
+You should receive the message "The <flagKey> feature flag evaluates to <flagValue>." The application will run continuously and react to the flag changes in LaunchDarkly.

src/main/java/Hello.java

@@ -67,7 +67,7 @@ public static void main(String... args) throws Exception {
 
     // Evaluate the feature flag for this context.
     boolean flagValue = client.boolVariation(FEATURE_FLAG_KEY, context, false);
-    showMessage("Feature flag '" + FEATURE_FLAG_KEY + "' is " + flagValue + " for this context");
+    showMessage("The '" + FEATURE_FLAG_KEY + "' feature flag evaluates to " + flagValue + ".");
 
     if (flagValue) {
       showBanner();
@@ -81,7 +81,7 @@ public static void main(String... args) throws Exception {
     // We set up a flag change listener so you can see flag changes as you change
     // the flag rules.
     client.getFlagTracker().addFlagValueChangeListener(FEATURE_FLAG_KEY, context, event -> {
-        showMessage("Feature flag '" + FEATURE_FLAG_KEY + "' is " + event.getNewValue() + " for this context");
+        showMessage("The '" + FEATURE_FLAG_KEY + "' feature flag evaluates to " + event.getNewValue() + ".");
 
         if (event.getNewValue().booleanValue()) {
           showBanner();