r.accumulate: Update the manual (#373)

* r.accumulate: Typo in the manual

* Reformat comparison with r.watershed accumulation output

* Merge paragraphs

grass7/raster/r.accumulate/r.accumulate.html

@@ -7,10 +7,10 @@ <h2>NOTES</h2>
 
 <h3>Flow accumulation</h3>
 
-Unlike <em>r.watershed</em>, <em>r.accumulate</em> does not require the
-elevation data to calculate weighted flow accumulation.  Instead, this module
-only uses a flow direction map to trace and accumulate the amount of flow
-draining through and including each cell.
+Unlike <em>r.watershed</em>, <em>r.accumulate</em> does not require elevation
+data to calculate weighted flow accumulation.  Instead, this module only uses a
+flow direction map to trace and accumulate the amount of flow draining through
+and including each cell.
 
 <p>With <b>-n</b> flag, the module will count the number of upstream cells plus
 one and convert it to the negative if any upstream cells are likely to receive
@@ -106,21 +106,20 @@ <h3>Flow accumulation</h3>
 <img src="r_accumulate_nc_example.png">
 
 <p>For some reason, there are slight differences between the two output maps.
+The yellow and purple cells show the difference raster map (<i>accum_diff</i>).
+The red arrows and numbers represent drainage directions
+(<i>drain_directions</i>) and flow accumulation by <em>r.watershed</em>
+(<i>flow_accum</i>), respectively. Note that some cells close to headwater
+cells are assigned 1 even though they are located downstream of other cells.
 
 <p><img src="r_accumulate_r_watershed_nc_example.png">
 
-<p>The yellow and purple cells show the difference raster map
-(<i>accum_diff</i>). The red arrows and numbers represent drainage directions
-(<i>drain_directions</i>) and flow accumulation (<i>flow_accum</i> from
-<em>r.watershed</em>), respectively. Note that some cells close to headwater
-cells are assigned 1 even if they are located downstream of other cells.
+<p>For comparison, these numbers show the new flow accumulation by
+<em>r.accumulate</em> (<i>flow_accum_new</i>). The same cells are properly
+accumulated from the headwater cells.
 
 <p><img src="r_accumulate_nc_comparison.png">
 
-<p>For comparison, these numbers show the new flow accumulation
-(<i>flow_accum_new</i> from <em>r.accumulate</em>). The same cells are properly
-accumulated from the headwater cells.
-
 <h3>Stream network delineation</h3>
 
 <p>Calculate flow accumulation and delineate stream networks at once:
@@ -247,7 +246,7 @@ <h3>Longest flow path calculation</h3>
 
 <h3>Longest flow path calculation and subwatershed delineation in one run</h3>
 
-<p>Calculate longest flow paths and delineate subwatersheds in one rune:
+<p>Calculate longest flow paths and delineate subwatersheds in one run:
 <div class="code"><pre>
 # set computational region
 g.region -p raster=elevation