Update doc strings for makecpt.py

pygmt/src/makecpt.py

@@ -81,7 +81,7 @@ def makecpt(**kwargs):
  ``background='i'`` to match the colors for the lowest and highest
  values in the input (instead of the output) CPT.
  color_model :
- ``[R|r|h|c][+c[label]]``.
+ [**R**\|\ **r**\|\ **h**\|\ **c**\ ][**+c**\ [*label*\ ]].
  Force output CPT to be written with r/g/b codes, gray-scale values or
  color name (**R**, default) or r/g/b codes only (**r**), or h-s-v codes
  (**h**), or c/m/y/k codes (**c**). Optionally or alternatively, append
@@ -93,7 +93,7 @@ def makecpt(**kwargs):
  labels from *start* (a single letter or an integer). Append - to build
  ranges *start*-*start+1* instead.
  series : list or str
- ``[min/max/inc[+b|l|n]|file|list]``.
+ [*min/max/inc*\ [**+b**\|\ **l**\|\ **n**\ ]\|\ *file*\|\ *list*\ ].
  Defines the range of the new CPT by giving the lowest and highest
  z-value (and optionally an interval). If this is not given, the
  existing range in the master CPT will be used intact. The values
@@ -102,7 +102,7 @@ def makecpt(**kwargs):
  For details on array creation, see
  :gmt-docs:`makecpt.html#generate-1d-array`.
  truncate : list or str
- ``zlo/zhi``.
+ *zlo/zhi*\ .
  Truncate the incoming CPT so that the lowest and highest z-levels are
  to *zlo* and *zhi*. If one of these equal NaN then we leave that end of
  the CPT alone. The truncation takes place before any resampling. See