Correct projection and region description in 'vectors.py' (#2040)

Author: yvonnefroehlich

examples/tutorials/advanced/vectors.py

@@ -218,7 +218,8 @@
 direction = np.linspace(-90, -90, 5)  # direction values = [-90. -90. -90. -90.]
 length = np.linspace(1.5, 1.5, 5)  # length values = [1.5 1.5 1.5 1.5]
 
-# Create a plot with coast, Mercator projection (M) over the continental US
+# Create a plot with coast,
+# Transverse Mercator projection (T) over Turkey and Syria
 fig = pygmt.Figure()
 fig.coast(
     region=[20, 50, 30, 45],