Improve formulation

Author: yvonnefroehlich

examples/gallery/lines/vector_heads_tails.py

@@ -30,8 +30,8 @@
 
 Note: Vectors were completely redesigned for GMT 5 which separated the vector
 head (a polygon) from the vector stem (a line). In GMT 4, the entire vector was
-a polygon. Thus, for plotting an arrow with a fill for both head and stem users
-have to follow the GMT 4 synthax explained at :gmt-docs:`plot.html#id13`.
+a polygon. Thus, to fill the entire vector with a color users have to follow the
+GMT 4 synthax explained at :gmt-docs:`plot.html#id13`.
 """
 
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