Tweaks to w3m.sh to improve TXT version of docs

Make headers and description terms more apparent, by adding
some more regexps into the `sed` that the HTML is piped through
before being sent to `w3m`.

magic/magic-docs/es_ES.UTF-8/index.txt

@@ -1,6 +1,6 @@
                   Tux Paint "Magic" Tool: List of Magic Tools
 
-Distorts
+                               ### Distorts ###
 
   * Blur
   * Sharpen
@@ -31,7 +31,7 @@ Distorts
   * Noise
   * Halftone
 
-Color Filters
+                             ### Color Filters ###
 
   * Negative
   * Opposite
@@ -53,7 +53,7 @@ Color Filters
   * Xor Colors
   * Bloom
 
-Picture Warps
+                             ### Picture Warps ###
 
   * Mirror
   * Flip
@@ -71,7 +71,7 @@ Picture Warps
   * Kaleido-4, Kaleido-6, and Kaleido-8
   * Rotate
 
-Painting
+                               ### Painting ###
 
   * Bricks
   * Spray Paint
@@ -104,7 +104,7 @@ Painting
   * Light
   * Fractal
 
-Pattern Painting
+                           ### Pattern Painting ###
 
   * Symmetry Left/Right
   * Symmetry Up/Down
@@ -116,14 +116,14 @@ Pattern Painting
   * Tessellation Pointy
   * Tessellation Flat
 
-Picture Decorations
+                          ### Picture Decorations ###
 
   * Blind
   * Checkerboard
   * Snow Ball
   * Snow Flake
 
-Projections
+                              ### Projections ###
 
   * 1-Point Draw
   * 1-Point Select
@@ -139,7 +139,7 @@ Projections
   * Oblique Draw
   * Oblique Select
 
-Artistic
+                               ### Artistic ###
 
   * Flower
   * Googly Eyes