MLECO-3186: Each use case should same namespace convention as KWS and ASR

Certain UCs required additional work due to case context variables which also
became part of a namespace in generated files.
Solution was to declare these extra variables as part of the UC namespace in the respective model.hpp files.
Additional changes to standardise use of namespaces may be required - proposing new task.

Minor typo and rewording of customizing.md in relevant sections included.

Signed-off-by: Liam Barry <liam.barry@arm.com>
Change-Id: Ie78f82a30be252cb841136ea5115f21fc8d762cb
diff --git a/.clang-format b/.clang-format
index b22d4c2..d53ffa1 100644
--- a/.clang-format
+++ b/.clang-format
@@ -52,5 +52,6 @@
   SplitEmptyFunction: false
   SplitEmptyRecord: false
   SplitEmptyNamespace: true
+NamespaceIndentation: Inner
 ---