Fixes #2615: upgrade guide improvements

docs/guide/upgrade-from-v1.md

@@ -81,8 +81,8 @@ Events
 ------
 
 There is no longer the need to define an `on`-method in order to define an event in Yii 2.0.
-Instead, you can use whatever event names. To attach a handler to an event, you should
-use the `on` method now:
+Instead, you can use whatever event names. To attach a handler to an event, you should now
+use the `on` method:
 
 ```php
 $component->on($eventName, $handler);
@@ -475,8 +475,8 @@ Auto-quoting Table and Column Names
 ------------------------------------
 
 Yii 2.0 supports automatic quoting of database table and column names. A name enclosed
-within double curly brackets is treated as a table name, and a name enclosed within
-double square brackets is treated as a column name. They will be quoted according to
+within double curly brackets i.e. `{{tablename}}` is treated as a table name, and a name enclosed within
+double square brackets i.e. `[[fieldname]]` is treated as a column name. They will be quoted according to
 the database driver being used:
 
 ```php
@@ -528,9 +528,9 @@ extensions in 2.0 [referer to corresponding guide section](extensions.md).
 Integration with Composer
 -------------------------
 
-Yii is fully inegrated with the package manager for PHP named Composer that resolves dependencies, keeps your code
-up to date updating it semi-automatically and manages autoloading for third party libraries no matter which autoloading
-these are using.
+Yii is fully inegrated with Composer, a well known package manager for PHP, that resolves dependencies, helps keeping
+your code up to date by allowing updating it with a single console command and manages autoloading for third party
+libraries no matter which autoloading these libraries are using.
 
 In order to learn more refer to [composer](composer.md) and [installation](installation.md) sections of the guide.