Use CommandContext as method parameter

- With annotation(@Command) model it's now possible to just
  add CommandContext and it will get resolved and doesn't
  cause it to appear as an option.
- Backport #779
- Fixes #990

spring-shell-docs/modules/ROOT/pages/commands/writing.adoc

@@ -1,7 +1,7 @@
 [[writing]]
 = Writing
 
-ifndef::snippets[:snippets: ../../test/java/org/springframework/shell/docs]
+ifndef::snippets[:snippets: ../../../../src/test/java/org/springframework/shell/docs]
 
 When something needs to get written into your console you can always
 use JDK's `System.out` which then goes directly into JDK's own streams.
@@ -17,9 +17,17 @@ to return anything given `CommandContext` contains reference to
 include::{snippets}/WritingSnippets.java[tag=reg-terminal-writer]
 ----
 
-It's possible to autowire `Terminal` to get access to its writer.
+If using `@Command` you can get access to `CommandContext` and get
+`Terminal` from there.
 
 [source, java, indent=0]
 ----
 include::{snippets}/WritingSnippets.java[tag=anno-terminal-writer]
 ----
+
+It's possible to autowire `Terminal` to get access to its writer.
+
+[source, java, indent=0]
+----
+include::{snippets}/WritingSnippets.java[tag=legacyanno-terminal-writer]
+----