Document defaults of pint.UnitRegistry (#1919)

This updates the doc-string to include the defaults for all parameters.

pint/registry.py

@@ -69,31 +69,38 @@ class UnitRegistry(GenericUnitRegistry[Quantity, Unit]):
  ----------
  filename :
  path of the units definition file to load or line-iterable object.
- Empty to load the default definition file.
+ Empty string to load the default definition file. (default)
  None to leave the UnitRegistry empty.
  force_ndarray : bool
  convert any input, scalar or not to a numpy.ndarray.
+ (Default: False)
  force_ndarray_like : bool
  convert all inputs other than duck arrays to a numpy.ndarray.
+ (Default: False)
  default_as_delta :
  In the context of a multiplication of units, interpret
  non-multiplicative units as their *delta* counterparts.
+ (Default: False)
  autoconvert_offset_to_baseunit :
  If True converts offset units in quantities are
  converted to their plain units in multiplicative
- context. If False no conversion happens.
+ context. If False no conversion happens. (Default: False)
  on_redefinition : str
  action to take in case a unit is redefined.
- 'warn', 'raise', 'ignore'
+ 'warn', 'raise', 'ignore' (Default: 'raise')
  auto_reduce_dimensions :
  If True, reduce dimensionality on appropriate operations.
+ (Default: False)
  autoconvert_to_preferred :
  If True, converts preferred units on appropriate operations.
+ (Default: False)
  preprocessors :
  list of callables which are iteratively ran on any input expression
- or unit string
+ or unit string or None for no preprocessor.
+ (Default=None)
  fmt_locale :
- locale identifier string, used in `format_babel`. Default to None
+ locale identifier string, used in `format_babel` or None.
+ (Default=None)
  case_sensitive : bool, optional
  Control default case sensitivity of unit parsing. (Default: True)
  cache_folder : str or pathlib.Path or None, optional