Correct syntax for error_bar of pygmt.Figure.plot (#2183)

Co-authored-by: Dongdong Tian <[email protected]>

pygmt/src/plot.py

@@ -118,9 +118,9 @@ def plot(self, data=None, x=None, y=None, size=None, direction=None, **kwargs):
         *dx/dy* [Default is no offset]. If *dy* is not given it is set
         equal to *dx*.
     error_bar : bool or str
-        [**+b**\|\ **d**\|\ **D**][**+xl**\|\ **r**\|\ *x0*]\
-        [**+yl**\|\ **r**\|\ *y0*][**+p**\ *pen*].
-        Draw symmetrical error bars. Full documentation is at
+        [**x**\|\ **y**\|\ **X**\|\ **Y**][**+a**\|\ **A**]\
+        [**+cl**\|\ **f**][**+n**][**+w**\ *cap*][**+p**\ *pen*].
+        Draw error bars. Full documentation is at
         :gmt-docs:`plot.html#e`.
     connection : str
         [**c**\|\ **n**\|\ **r**]\