Fix missing documentation for many clock faces:

* Move from .c to .h as needed for consistency.
* When missing from both, copy from pull request or wiki.
* When missing entirely, infer functionality from source code.

movement/watch_faces/settings/preferences_face.h

@@ -25,6 +25,57 @@
 #ifndef PREFERENCES_FACE_H_
 #define PREFERENCES_FACE_H_
 
+/*
+ * PREFERENCES face
+ *
+ * The Preferences watch face allows you to configure various options on your
+ * Sensor Watch. Like all other screens, you advance the field you’re setting
+ * with the Light button, and advance its value with the Alarm button. The
+ * Preferences watch face labels each setting with a two-letter code on the
+ * top row; the following list describes each setting and their options:
+ *
+ *  CL - Clock mode.
+ *      This setting allows you to select a 12-or 24-hour clock display. All
+ *      watch faces that support displaying the time will respect this setting;
+ *      for example, both Simple Clock, World Clock and Sunrise/Sunset will
+ *      display the time in 24 hour format if the 24 hour clock is selected here.
+ *
+ *  BT - Button tone.
+ *      This setting is only relevant if you installed the buzzer connector,
+ *      and it toggles the beep when changing modes. If Y, the buzzer will
+ *      sound a tone when Mode is pressed. Change to N to make the Mode
+ *      button silent.
+ *
+ *  TO - Timeout.
+ *      Sets the time until screens that time out (like Settings and Time Set)
+ *      snap back to the first screen. 60 seconds is a good default for the
+ *      stock firmware, but if you choose a custom firmware with faces that
+ *      you’d like to keep on screen for longer, you can set that here.
+ *
+ *  LE - Low Energy mode.
+ *      Sets the time until the watch enters its low energy sleep mode.
+ *      Options range from 1 hour to 7 days, or Never. The more often Sensor
+ *      Watch goes to sleep, the longer its battery will last — but you will
+ *      lose the seconds indicator while it is asleep. This setting allows
+ *      you to make a tradeoff between the device’s responsiveness and its
+ *      longevity.
+ *
+ *  LT - Light.
+ *      This setting has three screens.
+ *      The first lets you choose how long the LED should stay lit when the
+ *       LIGHT button is pressed. Options are 1 second, 3 seconds and 5
+ *       seconds, or “No LED” to disable the LED entirely.
+ *      The second screen, titled “blu” or “grn”, sets the intensity of the
+ *       blue or green LED depending on the target Sensor Board hardware.
+ *       Values range from 0 (off) to 15 (full intensity).
+ *      The third screen, “red”, sets the intensity of the red LED, again
+ *       from 0 to 15.
+ *      On the last two screens, the LED remains on so that you can see the
+ *      effect of mixing the two LED colors. On the Special Edition boards,
+ *      you’ll have red, blue and a variety of shades of pink and purple to
+ *      experiment with!
+ */
+
 #include "movement.h"
 
 void preferences_face_setup(movement_settings_t *settings, uint8_t watch_face_index, void ** context_ptr);