Fix bug in almostontop that truncated long prompts

Add collection of cursor line immediately after the previous command
completes and use this when calculating the number of lines required to
move the screen in order to display only the latest prompt.

prompt_fresh_setup

@@ -132,16 +132,14 @@ fresh_line_one() {
 
 # Executed before each prompt.
 fresh_almostontop_precmd() {
-  # TODO: store the cursor position for use in fresh_almostontop_preexec
   # CSI ESC[6n gets the cursor position in the form ESC[<row>;<column>R
   printf "\033[6n"
   # Discard prefix delimited by [
   read -s -d [
-  # Store the <row> delimited by ; in fresh_precmd_row
-  read -s -d \; fresh_precmd_row
+  # Store the <row> delimited by ; in row_before
+  read -s -d \; row_before
   # Discard suffix delimted by R otherwise it is output to the tty
   read -s -d R
-  # printf "$fresh_precmd_row\n"
 }
 
 # Executed just after a command has been read and is about to be executed.
@@ -159,7 +157,7 @@ fresh_almostontop_preexec() {
   let "down = $LINES - $row"
   printf "\033[${down}B"
   # Calculate the number of lines in the prompt
-  let "prompt_lines = ($row - $fresh_precmd_row) + 2"
+  let "prompt_lines = ($row - $row_before) + 2"
   # Print new lines to push the old command out of view
   let "new = $row - $prompt_lines"
   for (( i = 0; i < $new; i++ )); do