store [nfc]: Update outdated references to loadGlobalStore

These were supposed to be updated in commit
fc80be1
where we replaced loadGlobalStore with getGlobalStore.

`LiveGlobalBindings.load` is the only thing left analogous to the
previously referred to `loadGlobalStore` method. To avoid direct
referencce to this specific implementation on `GlobalStore`, mention
that loading it for the first time is expected to be asynchronous
instead.

Signed-off-by: Zixuan James Li <[email protected]>

Author: PIG208

lib/model/binding.dart

@@ -76,7 +76,7 @@ abstract class ZulipBinding {
   }
 
   /// Get the app's singleton [GlobalStore],
-  /// calling [loadGlobalStore] if not already loaded.
+  /// loading it asynchronously if not already loaded.
   ///
   /// Where possible, use [GlobalStoreWidget.of] to get access to a [GlobalStore].
   /// Use this method only in contexts like notifications where
@@ -312,7 +312,7 @@ class PackageInfo {
 
 /// A concrete binding for use in the live application.
 ///
-/// The global store returned by [loadGlobalStore], and consequently by
+/// The global store returned by [getGlobalStore], and consequently by
 /// [GlobalStoreWidget.of] in application code, will be a [LiveGlobalStore].
 /// It therefore uses a live server and live, persistent local database.
 ///

test/model/binding.dart

@@ -29,7 +29,7 @@ TestZulipBinding get testBinding => TestZulipBinding.instance;
 /// and [TestGlobalStore.add] to set up test data there.  Such test functions
 /// must also call [reset] to clean up the global store.
 ///
-/// The global store returned by [loadGlobalStore], and consequently by
+/// The global store returned by [getGlobalStore], and consequently by
 /// [GlobalStoreWidget.of] in application code, will be a [TestGlobalStore].
 class TestZulipBinding extends ZulipBinding {
   /// Initialize the binding if necessary, and ensure it is a [TestZulipBinding].