GIR: Add some missing (nullable) annotations

libgimp/gimpbrushselectbutton.c

@@ -302,9 +302,9 @@ gimp_brush_select_button_init (GimpBrushSelectButton *button)
 
 /**
  * gimp_brush_select_button_new:
- * @title:      Title of the dialog to use or %NULL means to use the default
+ * @title: (nullable): Title of the dialog to use or %NULL means to use the default
  *              title.
- * @brush_name: Initial brush name or %NULL to use current selection.
+ * @brush_name: (nullable): Initial brush name or %NULL to use current selection.
  * @opacity:    Initial opacity. -1 means to use current opacity.
  * @spacing:    Initial spacing. -1 means to use current spacing.
  * @paint_mode: Initial paint mode.  -1 means to use current paint mode.
@@ -381,7 +381,7 @@ gimp_brush_select_button_get_brush (GimpBrushSelectButton *button,
 /**
  * gimp_brush_select_button_set_brush:
  * @button: A #GimpBrushSelectButton
- * @brush_name: Brush name to set; %NULL means no change.
+ * @brush_name: (nullable): Brush name to set; %NULL means no change.
  * @opacity:    Opacity to set. -1.0 means no change.
  * @spacing:    Spacing to set. -1 means no change.
  * @paint_mode: Paint mode to set.  -1 means no change.

libgimp/gimpfontselectbutton.c

@@ -184,8 +184,8 @@ gimp_font_select_button_init (GimpFontSelectButton *button)
 
 /**
  * gimp_font_select_button_new:
- * @title:     Title of the dialog to use or %NULL to use the default title.
- * @font_name: Initial font name.
+ * @title: (nullable): Title of the dialog to use or %NULL to use the default title.
+ * @font_name: (nullable): Initial font name.
  *
  * Creates a new #GtkWidget that completely controls the selection of
  * a font.  This widget is suitable for placement in a table in a
@@ -235,7 +235,7 @@ gimp_font_select_button_get_font (GimpFontSelectButton *button)
 /**
  * gimp_font_select_button_set_font:
  * @button: A #GimpFontSelectButton
- * @font_name: Font name to set; %NULL means no change.
+ * @font_name: (nullable): Font name to set; %NULL means no change.
  *
  * Sets the current font for the font select button.
  *

libgimp/gimpgradientselectbutton.c

@@ -210,8 +210,8 @@ gimp_gradient_select_button_init (GimpGradientSelectButton *button)
 
 /**
  * gimp_gradient_select_button_new:
- * @title:         Title of the dialog to use or %NULL to use the default title.
- * @gradient_name: Initial gradient name.
+ * @title: (nullable): Title of the dialog to use or %NULL to use the default title.
+ * @gradient_name: (nullable): Initial gradient name.
  *
  * Creates a new #GtkWidget that completely controls the selection of
  * a gradient.  This widget is suitable for placement in a table in a
@@ -261,7 +261,7 @@ gimp_gradient_select_button_get_gradient (GimpGradientSelectButton *button)
 /**
  * gimp_gradient_select_button_set_gradient:
  * @button: A #GimpGradientSelectButton
- * @gradient_name: Gradient name to set.
+ * @gradient_name: (nullable): Gradient name to set.
  *
  * Sets the current gradient for the gradient select button.
  *

libgimp/gimppaletteselectbutton.c

@@ -183,8 +183,8 @@ gimp_palette_select_button_init (GimpPaletteSelectButton *button)
 
 /**
  * gimp_palette_select_button_new:
- * @title:        Title of the dialog to use or %NULL to use the default title.
- * @palette_name: Initial palette name.
+ * @title: (nullable): Title of the dialog to use or %NULL to use the default title.
+ * @palette_name: (nullable): Initial palette name.
  *
  * Creates a new #GtkWidget that completely controls the selection of
  * a palette.  This widget is suitable for placement in a table in a
@@ -234,7 +234,7 @@ gimp_palette_select_button_get_palette (GimpPaletteSelectButton *button)
 /**
  * gimp_palette_select_button_set_palette:
  * @button: A #GimpPaletteSelectButton
- * @palette_name: Palette name to set; %NULL means no change.
+ * @palette_name: (nullable): Palette name to set; %NULL means no change.
  *
  * Sets the current palette for the palette select button.
  *

libgimp/gimppatternselectbutton.c

@@ -230,8 +230,8 @@ gimp_pattern_select_button_init (GimpPatternSelectButton *button)
 
 /**
  * gimp_pattern_select_button_new:
- * @title:        Title of the dialog to use or %NULL to use the default title.
- * @pattern_name: Initial pattern name or %NULL to use current selection.
+ * @title: (nullable): Title of the dialog to use or %NULL to use the default title.
+ * @pattern_name: (nullable): Initial pattern name or %NULL to use current selection.
  *
  * Creates a new #GtkWidget that completely controls the selection of
  * a pattern.  This widget is suitable for placement in a table in a
@@ -281,7 +281,7 @@ gimp_pattern_select_button_get_pattern (GimpPatternSelectButton *button)
 /**
  * gimp_pattern_select_button_set_pattern:
  * @button: A #GimpPatternSelectButton
- * @pattern_name: Pattern name to set; %NULL means no change.
+ * @pattern_name: (nullable): Pattern name to set; %NULL means no change.
  *
  * Sets the current pattern for the pattern select button.
  *

libgimpwidgets/gimpframe.c

@@ -216,7 +216,7 @@ gimp_frame_get_label_spacing (GimpFrame *frame)
 
 /**
  * gimp_frame_new:
- * @label: text to set as the frame's title label (or %NULL for no title)
+ * @label: (nullable): text to set as the frame's title label (or %NULL for no title)
  *
  * Creates a #GimpFrame widget. A #GimpFrame is a HIG-compliant
  * variant of #GtkFrame. It doesn't render a frame at all but

libgimpwidgets/gimppatheditor.c

@@ -283,7 +283,7 @@ gimp_path_editor_init (GimpPathEditor *editor)
 /**
  * gimp_path_editor_new:
  * @title: The title of the #GtkFileChooser dialog which can be popped up.
- * @path:  The initial search path.
+ * @path: (nullable): The initial search path.
  *
  * Creates a new #GimpPathEditor widget.
  *
@@ -370,7 +370,7 @@ gimp_path_editor_get_path (GimpPathEditor *editor)
  * @path:   The new path to set.
  *
  * The elements of the initial search path must be separated with the
- * #G_SEARCHPATH_SEPARATOR character.
+ * %G_SEARCHPATH_SEPARATOR character.
  **/
 void
 gimp_path_editor_set_path (GimpPathEditor *editor,

libgimpwidgets/gimpsizeentry.c

@@ -443,7 +443,7 @@ gimp_size_entry_new (gint                       number_of_fields,
  * gimp_size_entry_add_field:
  * @gse:               The sizeentry you want to add a field to.
  * @value_spinbutton:  The spinbutton to display the field's value.
- * @refval_spinbutton: The spinbutton to display the field's reference value.
+ * @refval_spinbutton: (nullable): The spinbutton to display the field's reference value.
  *
  * Adds an input field to the #GimpSizeEntry.
  *