docs: Fix a few typos

There are small typos in:
- experiments/ILS.py
- experiments/gauss.py
- experiments/ukf_range.py
- kf_book/book_plots.py

Fixes:
- Should read `standard` rather than `standand`.
- Should read `search` rather than `seach`.
- Should read `object` rather than `obect`.
- Should read `measurement` rather than `measurment`.
- Should read `consistent` rather than `consistant`.

kf_book/book_plots.py

@@ -334,7 +334,7 @@ def IntSlider(value, **kwargs):
 
 def plot_measurements(xs, ys=None, dt=None, color='k', lw=1, label='Measurements',
                       lines=False, **kwargs):
-    """ Helper function to give a consistant way to display
+    """ Helper function to give a consistent way to display
     measurements in the book.
     """
     if ys is None and dt is not None:
@@ -357,7 +357,7 @@ def plot_measurements(xs, ys=None, dt=None, color='k', lw=1, label='Measurements
 
 
 def plot_residual_limits(Ps, stds=1.):
-    """ plots standand deviation given in Ps as a yellow shaded region. One std
+    """ plots standard deviation given in Ps as a yellow shaded region. One std
     by default, use stds for a different choice (e.g. stds=3 for 3 standard
     deviations.
     """