video: Implement get_kr_kb manually to fix capitalization

Capitalization is wrong in function and parameter/variable names:

    warning: method `get_Kr_Kb` should have a snake case name
       --> gstreamer-video/src/auto/enums.rs:515:12
        |
    515 |     pub fn get_Kr_Kb(&self) -> Option<(f64, f64)> {
        |            ^^^^^^^^^ help: convert the identifier to snake case (notice the capitalization): `get_kr_kb`
        |
        = note: `#[warn(non_snake_case)]` on by default

    warning: variable `Kr` should have a snake case name
       --> gstreamer-video/src/auto/enums.rs:518:21
        |
    518 |             let mut Kr = mem::MaybeUninit::uninit();
        |                     ^^ help: convert the identifier to snake case (notice the capitalization): `kr`

    warning: variable `Kb` should have a snake case name
       --> gstreamer-video/src/auto/enums.rs:519:21
        |
    519 |             let mut Kb = mem::MaybeUninit::uninit();
        |                     ^^ help: convert the identifier to snake case (notice the capitalization): `kb`

    warning: variable `Kr` should have a snake case name
       --> gstreamer-video/src/auto/enums.rs:525:17
        |
    525 |             let Kr = Kr.assume_init();
        |                 ^^ help: convert the identifier to snake case (notice the capitalization): `kr`

    warning: variable `Kb` should have a snake case name
       --> gstreamer-video/src/auto/enums.rs:526:17
        |
    526 |             let Kb = Kb.assume_init();
        |                 ^^ help: convert the identifier to snake case (notice the capitalization): `kb`

gstreamer-video/Gir.toml

@@ -19,7 +19,6 @@ external_libraries = [
 generate = [
     "GstVideo.VideoCodecFrameFlags",
     "GstVideo.VideoFormatFlags",
-    "GstVideo.VideoColorMatrix",
     "GstVideo.VideoMultiviewMode",
     "GstVideo.VideoMultiviewFramePacking",
     "GstVideo.VideoFilter",
@@ -551,3 +550,11 @@ status = "generate"
     manual = true
         [object.function.return]
         nullable = false
+
+[[object]]
+name = "GstVideo.VideoColorMatrix"
+status = "generate"
+    [[object.function]]
+    name = "get_Kr_Kb"
+    # Function and parameter name capitalization is wrong
+    ignore = true

gstreamer-video/src/lib.rs

@@ -41,6 +41,8 @@ pub use crate::caps_features::{
     CAPS_FEATURE_META_GST_VIDEO_GL_TEXTURE_UPLOAD_META, CAPS_FEATURE_META_GST_VIDEO_META,
     CAPS_FEATURE_META_GST_VIDEO_OVERLAY_COMPOSITION,
 };
+mod video_color_matrix;
+pub use video_color_matrix::*;
 mod video_format;
 pub use crate::video_format::*;
 mod video_format_info;

gstreamer-video/src/video_color_matrix.rs

@@ -0,0 +1,25 @@
+use std::mem;
+
+use glib::translate::ToGlib;
+
+impl crate::VideoColorMatrix {
+    pub fn get_kr_kb(&self) -> Result<(f64, f64), glib::BoolError> {
+        assert_initialized_main_thread!();
+        unsafe {
+            let mut kr = mem::MaybeUninit::uninit();
+            let mut kb = mem::MaybeUninit::uninit();
+            glib::glib_result_from_gboolean!(
+                ffi::gst_video_color_matrix_get_Kr_Kb(
+                    self.to_glib(),
+                    kr.as_mut_ptr(),
+                    kb.as_mut_ptr(),
+                ),
+                "{:?} is not a YUV matrix",
+                self
+            )?;
+            let kr = kr.assume_init();
+            let kb = kb.assume_init();
+            Ok((kr, kb))
+        }
+    }
+}