Galaxies: clarify wording of completion condition.

A user mailed me today having found it less than clear from the docs
that Galaxies will only accept a solution if the set of filled-in grid
edges consists of _exactly_ the ones that separate two distinct
regions, rather than consisting of _at least_ those and perhaps others
which neither break rotational symmetry or disconnect any region.

html/galaxies.html

@@ -1,8 +1,12 @@
 Galaxies
 <p>
-Draw lines along grid edges so as to divide the grid up into
+Draw lines along grid edges so as to divide the grid up into connected
-regions. Every region should have two-way rotational symmetry, and
+regions of squares.
-should contain exactly one dot which is in its centre.
+<p>
+Every region should have two-way rotational symmetry, should contain
+exactly one dot which is in its centre, and should contain no lines
+separating two of its own squares from each other. A region satisfying
+all of these requirements will be automatically highlighted.
 <p>
 Click on a grid edge to add or remove a line. Right-click on a dot
 and drag the mouse to place an arrow in a grid square pointing to

puzzles.but

@@ -2400,10 +2400,15 @@ increasingly complex reasoning to avoid having to backtrack.
 \cfg{winhelp-topic}{games.galaxies}
 
 You have a rectangular grid containing a number of dots. Your aim is
-to draw edges along the grid lines which divide the rectangle into
+to partition the rectangle into connected regions of squares, in such
-regions in such a way that every region is 180\u00b0{-degree}
+a way that every region is 180\u00b0{-degree} rotationally symmetric,
-rotationally symmetric, and contains exactly one dot which is
+and contains exactly one dot which is located at its centre of
-located at its centre of symmetry.
+symmetry.
+
+To enter your solution, you draw lines along the grid edges to mark
+the boundaries of the regions. The puzzle is complete when the marked
+lines on the grid are precisely those that separate two squares
+belonging to different regions.
 
 This puzzle was invented by \i{Nikoli} \k{nikoli-galaxies}, under
 the name \q{Tentai Show}; its name is commonly translated into
@@ -2418,11 +2423,11 @@ Galaxies was contributed to this collection by James Harvey.
 \IM{Galaxies controls} controls, for Galaxies
 
 Left-click on any grid line to draw an edge if there isn't one
-already, or to remove one if there is. When you create a valid
+already, or to remove one if there is. When you create a valid region
-region (one which is closed, contains exactly one dot, is
+(one which is closed, contains exactly one dot, is 180\u00b0{-degree}
-180\u00b0{-degree} symmetric about that dot, and contains no
+symmetric about that dot, and contains no extraneous edges between two
-extraneous edges inside it) it will be highlighted automatically; so
+of its own squares), it will be highlighted automatically; so your aim
-your aim is to have the whole grid highlighted in that way.
+is to have the whole grid highlighted in that way.
 
 During solving, you might know that a particular grid square belongs
 to a specific dot, but not be sure of where the edges go and which