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`.

experiments/ukf_range.py

@@ -36,7 +36,7 @@ class RadarSim(object):
         self.alt = self.alt + .1*randn()
         self.pos = self.pos + self.vel*self.dt
 
-        # add measurment noise
+        # add measurement noise
         err = self.pos * 0.05*randn()
         slant_dist = math.sqrt(self.pos**2 + self.alt**2)