Clarify in docs the argument types extract_objects() accepts [skip ci]
@@ -2019,11 +2019,13 @@ A build target is either an [executable](#executable),
previous versions. The default will eventually be changed to `true`
in a future version.
-- `extract_objects()` returns an opaque value representing the
- generated object files of arguments, usually used to take single
- object files and link them to unit tests or to compile some source
- files with custom flags. To use the object file(s) in another build
- target, use the `objects:` keyword argument.
+- `extract_objects(source1, source2, ...)` takes as its arguments
+ a number of source files as [`string`](#string-object) or
+ [`files()`](#files) and returns an opaque value representing the
+ object files generated for those source files. This is typically used
+ to take single object files and link them to unit tests or to compile
+ some source files with custom flags. To use the object file(s)
+ in another build target, use the `objects:` keyword argument.
- `full_path()` returns a full path pointing to the result target file.
NOTE: In most cases using the object itself will do the same job as
