[docs] put notes into quote blocks to highlight them

doc/01-basic-usage.md

@@ -24,8 +24,7 @@ To check if composer is working, just run the PHAR through `php`:
 
 This should give you a list of available commands.
 
-**Note:** You can also perform the checks only without downloading composer
-by using the `--check` option. For more information, just use `--help`.
+> **Note:** You can also perform the checks only without downloading composer by using the `--check` option. For more information, just use `--help`.
 
     $ curl -s http://getcomposer.org/installer | php -- --help
 
@@ -165,4 +164,4 @@ $loader = require 'vendor/.composer/autoload.php';
 $loader->add('Acme\Test', __DIR__);
 ```
 
-**Note:** Composer provides its own autoloader. If you don't want to use that one, you can just include `vendor/.composer/autoload_namespaces.php`, which returns an associative array mapping namespaces to directories.
+> **Note:** Composer provides its own autoloader. If you don't want to use that one, you can just include `vendor/.composer/autoload_namespaces.php`, which returns an associative array mapping namespaces to directories.

doc/02-libraries.md

@@ -19,7 +19,7 @@ In order to make that package installable you need to give it a name. You do thi
 
 In this case the project name is `acme/hello-world`, where `acme` is the vendor name. Supplying a vendor name is mandatory.
 
-**Note:** If you don't know what to use as a vendor name, your GitHub username is usually a good bet. While package names are case insensitive, the convention is all lowercase and dashes for word separation.
+> **Note:** If you don't know what to use as a vendor name, your GitHub username is usually a good bet. While package names are case insensitive, the convention is all lowercase and dashes for word separation.
 
 ## Specifying the version
 
@@ -48,7 +48,7 @@ Here are a few examples of valid tag names:
     v2.0.0-alpha
     v2.0.4-p1
 
-**Note:** If you specify an explicit version in `composer.json`, the tag name must match the specified version.
+> **Note:** If you specify an explicit version in `composer.json`, the tag name must match the specified version.
 
 ### Branches
 
@@ -61,7 +61,7 @@ Here are some examples of version branch names:
     1.1.x
     1.1.*
 
-**Note:** When you install a dev version, it will install it from source. See [Repositories] for more information.
+> **Note:** When you install a dev version, it will install it from source. See [Repositories] for more information.
 
 ## Lock file