Implement newline cursor feature with one option instead of three

Per bobthecow:

"In keeping with bobthefish's goal to be opinionated but flexible,
let's do this with one option, not three. I'm leaning toward:

set -g theme_cursor_on_new_line yes
Then:

Always show the arrow at the end of the first line
Always show a minimalist arrow at the start of the next line"

README.md

@@ -42,8 +42,6 @@ This theme is based loosely on [agnoster][agnoster].
      * Background jobs (**`%`**)
      * You currently have superpowers (**`$`**)
      * Cursor on newline
-       * Prefix newline with right arrow glyph
-       * Keep right arrow glyph on live above newline
  * Current vi mode
  * `User@Host` (unless you're the default user)
  * Current RVM, rbenv or chruby (Ruby) version
@@ -96,8 +94,6 @@ set -g theme_color_scheme dark
 set -g fish_prompt_pwd_dir_length 0
 set -g theme_project_dir_length 1
 set -g theme_newline_cursor yes
-set -g theme_newline_cursor_arrow_glyph no
-set -g theme_newline_cursor_top_arrow_glyph no
 ```
 
 **Title options**
@@ -116,8 +112,6 @@ set -g theme_newline_cursor_top_arrow_glyph no
 - `fish_prompt_pwd_dir_length`. bobthefish respects the Fish `$fish_prompt_pwd_dir_length` setting to abbreviate the prompt path. Set to `0` to show the full path, `1` (default) to show only the first character of each parent directory name, or any other number to show up to that many characters.
 - `theme_project_dir_length`. The same as `$fish_prompt_pwd_dir_length`, but for the path relative to the current project root. Defaults to `0`; set to any other number to show an abbreviated path.
 - `theme_newline_cursor`. Use `yes` to have cursor start on a new line. By default the prompt is only one line. When working with long directories it may be preferrend to have cursor on the next line.
-- `theme_newline_cursor_arrow_glyph`. Use `no` have the new line start with a blank space. By default, the default right arrow glyph will be used followed by a single space (' '). Note that this space is required to have a correctly functioning right prompt.
-- `theme_newline_cursor_top_arrow_glyph`. Use `no` to remove the right arrow glyph on the original (top) command prompt line. By default, the right arrow glyph will be used.
 
 **Color scheme options**
 

fish_prompt.fish

@@ -37,8 +37,6 @@
 #     set -g fish_prompt_pwd_dir_length 0
 #     set -g theme_project_dir_length 1
 #     set -g theme_newline_cursor yes
-#     set -g theme_newline_cursor_arrow_glyph no
-#     set -g theme_newline_cursor_top_arrow_glyph no
 
 # ===========================
 # Helper methods
@@ -279,16 +277,17 @@ function __bobthefish_finish_segments -S -d 'Close open prompt segments'
   if [ "$__bobthefish_current_bg" != '' ]
     set_color normal
     set_color $__bobthefish_current_bg
-    if not [ "$theme_newline_cursor_top_arrow_glyph" = 'no' ]
-      echo -ns $__bobthefish_right_black_arrow_glyph
-    end
-    if [ "$theme_newline_cursor" = 'yes' ]
-      echo -ens "\n"
-    end
-    if not [ "$theme_newline_cursor_arrow_glyph" = 'no' ]
-      echo -ns "$__bobthefish_right_black_arrow_glyph"
+    echo -ns $__bobthefish_right_black_arrow_glyph ' '
+  end
+
+  if [ "$theme_newline_cursor" = 'yes' ]
+    echo -ens "\n"
+    set_color $fish_color_autosuggestion
+    if [ "$theme_powerline_fonts" = "no" ]
+      echo -ns '> '
+    else
+      echo -ns "$__bobthefish_right_arrow_glyph "
     end
-    echo -n ' '
   end
 
   set_color normal