libcamera: Rename 'method' to 'function'

Usage of 'method' to refer to member functions comes from Java. The C++
standard uses the term 'function' only. Replace 'method' with 'function'
or 'member function' through the whole code base and documentation.
While at it, fix two typos (s/backeng/backend/).

The BoundMethod and Object::invokeMethod() are left as-is here, and will
be addressed separately.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>
Acked-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

src/libcamera/formats.cpp

@@ -16,7 +16,7 @@
 
 /**
  * \file internal/formats.h
- * \brief Types and helper methods to handle libcamera image formats
+ * \brief Types and helper functions to handle libcamera image formats
  */
 
 namespace libcamera {