DOC: fix typos/mistakes

doc/constraints.rst

@@ -13,7 +13,7 @@ highly desirable to place mathematical constraints on parameter values.
 For example, one might want to require that two Gaussian peaks have the
 same width, or have amplitudes that are constrained to add to some value.
 Of course, one could rewrite the objective or model function to place such
-requirements, but this is somewhat error prone, and limits the flexibility
+requirements, but this is somewhat error-prone, and limits the flexibility
 so that exploring constraints becomes laborious.
 
 To simplify the setting of constraints, Parameters can be assigned a

doc/fitting.rst

@@ -129,7 +129,7 @@ Choosing Different Fitting Methods
 By default, the `Levenberg-Marquardt
 <https://en.wikipedia.org/wiki/Levenberg-Marquardt_algorithm>`_ algorithm is
 used for fitting. While often criticized, including the fact it finds a
-*local* minima, this approach has some distinct advantages. These include
+*local* minimum, this approach has some distinct advantages. These include
 being fast, and well-behaved for most curve-fitting needs, and making it
 easy to estimate uncertainties for and correlations between pairs of fit
 variables, as discussed in :ref:`fit-results-label`.
@@ -476,7 +476,7 @@ be used to abort a fit.
    :type  resid:  numpy.ndarray
    :param args:  Positional arguments. Must match ``args`` argument to :func:`minimize`
    :param kws:   Keyword arguments. Must match ``kws`` argument to :func:`minimize`
-   :return:      Residual array (generally ``data-model``) to be minimized in the least-squares sense.
+   :return:      Iteration abort flag.
    :rtype:    None for normal behavior, any value like ``True`` to abort the fit.
 
 

doc/model.rst

@@ -378,7 +378,7 @@ Parameters if the supplied default value was a valid number (but not
 .. jupyter-execute::
 
     def decay2(t, tau, N=10, check_positive=False):
-        if check_small:
+        if check_positive:
             arg = abs(t)/max(1.e-9, abs(tau))
         else:
             arg = t/tau