Update pygmt/base_plotting.py

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

pygmt/base_plotting.py

@@ -122,7 +122,7 @@ def coast(self, **kwargs):
  **+l** for lakes or **+r** for river-lakes, and passing multiple
  strings in a list.
  resolution : str
- **f**\ |**h**\ |**i**\ |**l**\ |**c**
+ **f**\|\ **h**\|\ **i**\|\ **l**\|\ **c**
  Selects the resolution of the data set to: (**f**\ )ull,
  (**h**\ )igh, (**i**\ )ntermediate, (**l**\ )ow,
  and (**c**\ )rude).