api!: remove dc_msg_force_plaintext

Message.force_plaintext() is still used in legacy SecureJoin steps
internally, so cannot be removed, but there is no need for public API.

deltachat-ffi/deltachat.h

@@ -4973,17 +4973,6 @@ uint32_t        dc_msg_get_original_msg_id    (const dc_msg_t* msg);
  */
 uint32_t        dc_msg_get_saved_msg_id     (const dc_msg_t* msg);
 
-
-/**
- * Force the message to be sent in plain text.
- *
- * This API is for bots, there is no need to expose it in the UI.
- *
- * @memberof dc_msg_t
- * @param msg The message object.
- */
-void            dc_msg_force_plaintext        (dc_msg_t* msg);
-
 /**
  * @class dc_contact_t
  *

deltachat-ffi/src/lib.rs

@@ -4054,16 +4054,6 @@ pub unsafe extern "C" fn dc_msg_get_saved_msg_id(msg: *const dc_msg_t) -> u32 {
     })
 }
 
-#[no_mangle]
-pub unsafe extern "C" fn dc_msg_force_plaintext(msg: *mut dc_msg_t) {
-    if msg.is_null() {
-        eprintln!("ignoring careless call to dc_msg_force_plaintext()");
-        return;
-    }
-    let ffi_msg = &mut *msg;
-    ffi_msg.message.force_plaintext();
-}
-
 // dc_contact_t
 
 /// FFI struct for [dc_contact_t]

python/src/deltachat/message.py

@@ -254,10 +254,6 @@ class Message:
         """Quote setter."""
         lib.dc_msg_set_quote(self._dc_msg, quoted_message._dc_msg)
 
-    def force_plaintext(self) -> None:
-        """Force the message to be sent in plain text."""
-        lib.dc_msg_force_plaintext(self._dc_msg)
-
     @property
     def error(self) -> Optional[str]:
         """Error message."""

src/message.rs

@@ -1319,7 +1319,7 @@ impl Message {
     }
 
     /// Force the message to be sent in plain text.
-    pub fn force_plaintext(&mut self) {
+    pub(crate) fn force_plaintext(&mut self) {
         self.param.set_int(Param::ForcePlaintext, 1);
     }