Add docstrings to frequency_merge (#115)

* Added docstrings to frequency_merge function.

* Format

* Update freqs.py

---------

Co-authored-by: Setsugennoao <[email protected]>

vsdenoise/freqs.py

@@ -22,6 +22,38 @@ def frequency_merge(
     mean_diff: bool = False, planes: PlanesT = None, mv_args: KwargsT | None = None,
     **kwargs: Any
 ) -> vs.VideoNode:
+    """
+    Merges the frequency components of the input clips.
+    
+    :param _clips:      The clips to merge.
+    :param tr:          The temporal radius to use for motion compensation.
+    :param mode_high:   The mode to use for the high frequency components or
+                        specifying the clip with the high frequency components.
+    :param mode_low:    The mode to use for the low frequency components or
+                        specifying the clip with the low frequency components.
+    :param mode_tr:     The mode to use for motion compensation.
+                        If None, it defaults to the value of mode_high.
+    :param lowpass:     The lowpass filter to used to extract low frequency components.
+                            Example: 
+                                ```
+                                    lowpass=[
+                                        None,
+                                        lambda i: core.fmtc.resample(
+                                            i,
+                                            h=1080,
+                                            w=1920,
+                                            kernel="lanczos",
+                                            taps=[4, 2],
+                                            fv=[1 / 1.25, 1 / 1.375],
+                                            fh=[1 / 1.25, 1 / 1.375],
+                                        )
+                                ```
+    :param mean_diff:   Whether to use the mean of the lowpass filter and the original clip to
+                        extract the low frequency components. Default is False.
+    :param planes:      The planes to process. If None, all planes will be processed.
+    :param mv_args:     The arguments to pass to the MVTools class.
+    """
+
     clips = flatten_vnodes(_clips)
     n_clips = len(clips)