Doxify bfu/style

Also fixes an old misleading comment noticed by kon.

src/bfu/style.c

@@ -1,4 +1,5 @@
-/* BFU display helpers. */
+/** BFU style/color cache
+ * @file */
 
 #ifdef HAVE_CONFIG_H
 #include "config.h"

src/bfu/style.h

@@ -4,11 +4,27 @@
 struct color_pair;
 struct terminal;
 
-/* Get the colors of the bfu element. If @color is 0 a style suitable for
+/** Get suitable BFU color for the specific terminal
- * mono terminals is returned else a style for a color terminal. */
+ *
+ * Get a color pair (foreground- and background color) for a specific
+ * BFU widget "style". Depending on the terminal settings a color
+ * suitable for either mono terminals or color terminals is returned.
+ * The returned color is derived by looking up the specified stylename
+ * under the option tree of "ui.colors.color" or the "ui.colors.mono",
+ * and using the values of the "text" and "background" color options as
+ * the values of the color pair.
+ *
+ * @param term		Terminal for which the color will be used.
+ * @param stylename	The name of the BFU color.
+ * @return		A color pair matching the stylename or NULL.
+ */
 struct color_pair *
 get_bfu_color(struct terminal *term, unsigned char *stylename);
 
+/** Cleanup after the BFU style cache
+ *
+ * Free all resources used by the BFU style cache.
+ */
 void done_bfu_colors(void);
 
 #endif