Update man pages of games (demo programs), add glpuzzle.man

Prepare for installation of `games` demo programs. Fix inconsistencies
and typos in man pages. In the future the man pages can be installed
together with the executables. This will be done in a later commit.

documentation/src/glpuzzle.man: new file.

Backported from master (eb1e0f423d).

documentation/src/blocks.man

@@ -1,18 +1,18 @@
-.TH blocks 6 "FLTK Checkers" "15 January 2006"
+.TH blocks 6 "FLTK Checkers" "03 March 2025"
 .SH NAME
 blocks \- the fltk block attack! game
 .sp
 .SH SYNOPSIS
 \fIBlocks\fR is a FLTK-based block elimination game. Stacks of
 colored blocks move from right to left as you try to eliminate
-groups adjacent blocks by clicking on them. As the game
+groups of adjacent blocks by clicking on them. As the game
 progresses, more colors are added (up to a maximum of 7) and the
 blocks move faster and faster.
 .SH GAME PLAY
-Press the N key to start a game. As the blocks move across the
+Press the spacebar to start a game. As the blocks move across the
 window, click on groups of two or more blocks to clear them - the
 larger the number of adjacent blocks, the greater the score.
-Clicking on a blocks containing a dark ball will clear all blocks
+Clicking on a block containing a dark ball will clear all blocks
 of that color, however you will score much fewer points than a
 normal click. The game is over when the blocks reach the left
 side of the window.

documentation/src/checkers.man

@@ -1,4 +1,4 @@
-.TH checkers 6 "FLTK Checkers" "15 January 2006"
+.TH checkers 6 "FLTK Checkers" "03 March 2025"
 .SH NAME
 checkers \- the fltk checkers game
 .sp
@@ -8,11 +8,11 @@ The game is played on an 8x8 board with each player starting with
 12 pieces or "checkers" on opposite sides of the board. The
 computer plays the white checkers in this version of the game.
 .LP
-The object of the game is to remove all of your opponents pieces.
+The object of the game is to remove all of your opponents' pieces.
 Players move one of their pieces diagonally forward on each move,
 either a single space or by "jumping" an adjacent piece. Your
-opponents pieces are removed by jumping them - you can make
-multiple jumps in a single turn.
+opponents' pieces are removed by jumping them - you can make
+multiple jumps in a single turn. You \fImust\fR jump if you can!
 .LP
 If a piece reaches the other side of the board, it is converted
 to a "king" which can move both forwards and backwards.

documentation/src/glpuzzle.man

@@ -0,0 +1,34 @@
+.TH glpuzzle 6 "FLTK glpuzzle" "03 March 2025"
+.SH NAME
+glpuzzle \- the fltk glpuzzle game
+.sp
+.SH SYNOPSIS
+\fIglpuzzle\fR is a FLTK-based version of the game of glpuzzle, a
+sliding pieces game whose object is to move the gray piece out of the
+box at the bottom.
+.LP
+At the start of a new game, glpuzzle fills in a standard placement of
+pieces. You can move individual pieces around by clicking and dragging
+with the left mouse button until the gray piece can be slided out at
+the bottom of the box.
+.LP
+Hit the 'D' key to delete a selected piece to simplify the game.
+.LP
+Hit the 'S' key to watch the puzzle being solved automatically.
+Hit the 'S' key again to stop solving.
+.LP
+Hit the 'R' key to reset the puzzle to its starting position.
+.LP
+Clicking with the left mouse button on a free part of the box and
+dragging the mouse starts spinning the box. Click anywhere else to
+stop the spinning.
+.LP
+Hit the spacebar or 'N' key to reposition the game to the normal view.
+.LP
+Click with the right mouse button to open a menu.
+.SH SEE ALSO
+fltk(3)
+.br
+FLTK Web Site, https://www.fltk.org/
+.SH AUTHOR
+Bill Spitzak and others, original author unknown (OpenGL).

documentation/src/sudoku.man

@@ -1,4 +1,4 @@
-.TH sudoku 6 "FLTK Sudoku" "15 January 2006"
+.TH sudoku 6 "FLTK Sudoku" "03 March 2025"
 .SH NAME
 sudoku \- the fltk sudoku game
 .sp
@@ -8,17 +8,15 @@ Sudoku (pronounced soo-dough-coo with the emphasis on the first
 syllable) is a simple number-based puzzle/game played on a 9x9
 grid that is divided into 3x3 subgrids. The goal is to enter a
 number from 1 to 9 in each cell so that each number appears only
-once in each column and row.
+once in each column, row, and subgrid.
 .LP
 At the start of a new game, Sudoku fills in a random selection of
 cells for you - the number of cells depends on the difficulty
 level you use. Click in any of the empty cells or use the arrow
 keys to highlight individual cells and press a number from 1 to 9
 to fill in the cell. To clear a cell, press 0, Delete, or
-Backspace. As you complete each subgrid, correct subgrids are
-highlighted in green. When you have successfully completed all
-subgrids, the entire puzzle is highlighted until you start a new
-game.
+Backspace. When you have successfully completed all subgrids,
+the entire puzzle is highlighted until you start a new game.
 .LP
 As you work to complete the puzzle, you can display possible
 solutions inside each cell by holding the Shift key and pressing