Keymap: Change GetModifiedCharacters API to return BStringList.

Simplifies the API and makes ownership semantics clearer.

Change-Id: I59d2e3ef8055253e85943500fb65356762055c54
Reviewed-on: https://review.haiku-os.org/c/haiku/+/8914
Reviewed-by: waddlesplash <[email protected]>

headers/private/shared/Keymap.h

@@ -12,7 +12,7 @@
 
 #include <DataIO.h>
 #include <InterfaceDefs.h>
-#include <ObjectList.h>
+#include <StringList.h>
 
 
 class BKeymap {
@@ -41,7 +41,7 @@ public:
 									int32* numBytes) const;
 			status_t			GetModifiedCharacters(const char* in,
 									int32 inModifiers, int32 outModifiers,
-									BObjectList<const char>* _outList);
+									BStringList& _outList);
 
 			const key_map&		Map() const { return fKeys; }