Fix typos

Closes gh-4093

CONTRIBUTING.adoc

@@ -180,7 +180,7 @@ Maven is well supported by most Java IDEs. Refer to your vendor documentation.
 
 
 == Integration tests
-The sample application are used as integration tests during the build (when you
+The sample applications are used as integration tests during the build (when you
 `mvn install`). Due to the fact that they make use of the `spring-boot-maven-plugin`
 they cannot be called directly, and so instead are launched via the
 `maven-invoker-plugin`. If you encounter build failures running the integration tests,

spring-boot-docs/src/main/asciidoc/using-spring-boot.adoc

@@ -563,7 +563,7 @@ Searching for `+enable*+` annotations can be a good starting point.
 === Importing additional configuration classes
 You don't need to put all your `@Configuration` into a single class. The `@Import`
 annotation can be used to import additional configuration classes. Alternatively, you
-can use `@ComponentScan` to automatically pickup all Spring components, including
+can use `@ComponentScan` to automatically pick up all Spring components, including
 `@Configuration` classes.
 
 
@@ -598,7 +598,7 @@ configuration to replace specific parts of the auto-configuration. For example,
 you add your own `DataSource` bean, the default embedded database support will back away.
 
 If you need to find out what auto-configuration is currently being applied, and why,
-starting your application with the `--debug` switch. This will log an auto-configuration
+start your application with the `--debug` switch. This will log an auto-configuration
 report to the console.