[gtksourceview] completioncell: add gi-doc for set_text()

[Christian Hergert <chergert src gnome org>]

commit 46bf1874fbd0df0d25617b79408ca6772d29fd1d
Author: Christian Hergert <chergert redhat com>
Date:   Tue Apr 19 10:52:18 2022 -0700

    completioncell: add gi-doc for set_text()

 gtksourceview/gtksourcecompletioncell.c | 7 +++++++
 1 file changed, 7 insertions(+)
---
diff --git a/gtksourceview/gtksourcecompletioncell.c b/gtksourceview/gtksourcecompletioncell.c
index f3dc8f5f..2829454a 100644
--- a/gtksourceview/gtksourcecompletioncell.c
+++ b/gtksourceview/gtksourcecompletioncell.c
@@ -266,6 +266,13 @@ gtk_source_completion_cell_set_markup (GtkSourceCompletionCell *self,
        gtk_label_set_use_markup (GTK_LABEL (self->child), TRUE);
 }
 
+/**
+ * gtk_source_completion_cell_set_text:
+ * @self: a #GtkSourceCompletionCell
+ * @text: (nullable): the text to set or %NULL
+ *
+ * Sets the text for the column cell. Use %NULL to unset.
+ */
 void
 gtk_source_completion_cell_set_text (GtkSourceCompletionCell *self,
                                      const char              *text)