This pr fixes the header file name from `lldb_forward.h` to `lldb-forward.h` in `sbapi.rst`. Here is the header file in question: [lldb-forward.h](https://github.com/llvm/llvm-project/blob/main/lldb/include/lldb/lldb-forward.h). Signed-off-by: Nikita B <n2h9z4@gmail.com>