Added the alternate push pull function (#35)

* Added the alternate push pull function

* Renamed functions

Renamed (into_alternate -> into_alternate_open_drain) and (into_alternate_push_pull -> into_alternate)

* Explicitly set push-pull in into_alternate

Co-authored-by: Nando Bongers <[email protected]>

Author: NandoBongers

src/gpio.rs

@@ -520,6 +520,9 @@ macro_rules! gpio {
                             gpio.moder.modify(|r, w| {
                                 w.bits((r.bits() & !(0b11 << offset)) | (0b10 << offset))
                             });
+                            gpio.otyper.modify(|r, w| {
+                                w.bits(r.bits() & !(0b1 << $i))
+                            });
                         }
                         $PXi { _mode: PhantomData }
                     }