Fix typo ("vertical" -> "horizontal")

Author: jsvine

README.md

@@ -193,7 +193,7 @@ You can pass explicit coordinates or any `pdfplumber` PDF object (e.g., char, li
 |----------------------|-------------|-------------|
 |`im.draw_line(line, stroke={color}, stroke_width=1)`| `im.draw_lines(list_of_lines, **kwargs)`| Draws a line from a `line`-like object, or a 4-tuple bounding box.|
 |`im.draw_vline(location, stroke={color}, stroke_width=1)`| `im.draw_vlines(list_of_locations, **kwargs)`| Draws a vertical line at the x-coordinate indicated by `location`.|
-|`im.draw_hline(location, stroke={color}, stroke_width=1)`| `im.draw_hlines(list_of_locations, **kwargs)`| Draws a vertical line at the y-coordinate indicated by `location`.|
+|`im.draw_hline(location, stroke={color}, stroke_width=1)`| `im.draw_hlines(list_of_locations, **kwargs)`| Draws a horizontal line at the y-coordinate indicated by `location`.|
 |`im.draw_rect(bbox_or_obj, fill={color}, stroke={color}, stroke_width=1)`| `im.draw_rects(list_of_rects, **kwargs)`| Draws a rectangle from a `rect`, `char`, etc., or 4-tuple bounding box.|
 |`im.draw_circle(center_or_obj, radius=5, fill={color}, stroke={color})`| `im.draw_circles(list_of_circles, **kwargs)`| Draws a circle at `(x, y)` coordinate or at the center of a `char`, `rect`, etc.|