minor #5383 Reword a paragraph about service configurations (richardudovich)

This PR was submitted for the 2.7 branch but it was merged into the 2.3 branch instead (closes #5383).

Discussion
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Reword a paragraph about service configurations

Commits
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b63fa61 Improved wording
a0f3f82 remove the two lines
aa1f56b Reword a paragraph about service configurations

Author: weaverryan

book/service_container.rst

@@ -318,10 +318,11 @@ The service container is built using a single configuration resource
 be imported from inside this file in one way or another. This gives you absolute
 flexibility over the services in your application.
 
-External service configuration can be imported in two different ways. The
-first - and most common method - is via the ``imports`` directive. Later, you'll
-learn about the second method, which is the flexible and preferred method
-for importing service configuration from third-party bundles.
+External service configuration can be imported in two different ways. The first 
+method, commonly used to import container configuration from the bundles you've 
+created - is via the ``imports`` directive. The second method, although slightly more 
+complex offers more flexibility and is commonly used to import third-party bundle 
+configuration. Read on to learn more about both methods.
 
 .. index::
    single: Service Container; Imports