Update distcalc doc

pygmt/helpers/decorators.py

@@ -21,17 +21,17 @@
  *projection*\ [*projection-specific arguments*\ ]\ *figure size*.
  Select map projection. This is a required argument if this
  is the first plot command.""",
- "B": r"""frame : str or list
+ "B": """frame : bool or str or list
  Set map boundary frame and axes attributes.""",
  "U": r"""timestamp : bool or str
  Draw GMT time stamp logo on plot.""",
- "CPT": r"""cmap : str
+ "CPT": """cmap : str
  File name of a CPT file or ``C='color1,color2[,color3,...]'`` to
  build a linear continuous CPT from those colors automatically.""",
- "G": r"""color : str
+ "G": """color : str
  Select color or pattern for filling of symbols or polygons. Default
  is no fill.""",
- "V": r"""verbose : str
+ "V": """verbose : str
  Select verbosity level [Default is w], which modulates the messages
  written to stderr. Choose among 7 levels of verbosity:
  - **q** - Quiet, not even fatal error messages are produced
@@ -41,7 +41,7 @@
  - **i** - Informational messages (same as "verbose=True")
  - **c** - Compatibility warnings
  - **d** - Debugging messages""",
- "W": r"""pen : str
+ "W": """pen : str
  Set pen attributes for lines or the outline of symbols.""",
  "XY": r"""xshift : str
  [**a**\|\ **c**\|\ **f**\|\ **r**\][*xshift*]. 
@@ -52,7 +52,7 @@
  Shift plot origin in y-direction. Full documentation is at
  :gmt-docs:`gmt.html#xy-full`.""",
  "j": r"""distcalc : str
- ``e|f|g``.
+ **e**\|\ **f**\|\ **g**.
  Determine how spherical distances are calculated.
  - **e** - Ellipsoidal (or geodesic) mode
  - **f** - Flat Earth mode