Update README for iWebApkApi.java inside runtime_library to include a final...

Update README for iWebApkApi.java inside runtime_library to include a final "git cl format" command.

The reason for this CL is that, in certain scenarios where the aidl has to be updated to handle more complicated parameters (such as list of ParcelFileDescriptors), then it won't actually work until I run a git cl format to fix the iWebApkApi java file.

Change-Id: I1bb184b4edaa576a4b23994cf5018262f0b0ebd5
Reviewed-on: https://chromium-review.googlesource.com/c/1344211
Commit-Queue: Ethan Xu <xuethan@google.com>
Reviewed-by: Peter Kotwicz <pkotwicz@chromium.org>
Reviewed-by: Glenn Hartmann <hartmanng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#609912}

chrome/android/webapk/shell_apk/current_version/current_version.gni

@@ -12,4 +12,4 @@
 # //chrome/android/webapk/shell_apk:webapk is changed. This includes
 # Java files, Android resource files and AndroidManifest.xml. Does not affect
 # Chrome.apk
-current_shell_apk_version = 75
+current_shell_apk_version = 76

chrome/android/webapk/shell_apk/src/org/chromium/webapk/lib/runtime_library/README

@@ -4,7 +4,8 @@ as the app targets Android O a notification channel was necessary for the
 notification to be shown. Since the runtime library is provided by the host
 browser, there's no way to guarantee this with the WebAPK shell change.
 
-To update this generated copy again,
+To update this generated copy again:
 $ ninja -C out/Debug webapk_runtime_library
 $ unzip out/Debug/gen/chrome/android/webapk/libs/runtime_library/webapk_service_aidl.srcjar
 $ mv org/chromium/webapk/lib/runtime_library/IWebApkApi.java chrome/android/webapk/shell_apk/src/org/chromium/webapk/lib/runtime_library/
+$ git cl format