Migrate qe.timeit instances back to qe.Timer() with milliseconds for SciPy

Co-authored-by: mmcky <8263752+mmcky@users.noreply.github.com>

Author: Copilot

lectures/parallelization.md

@@ -166,7 +166,8 @@ x, y = np.meshgrid(grid, grid)
 ```
 
 ```{code-cell} ipython3
-qe.timeit(lambda: np.max(f(x, y)), runs=3)
+with qe.Timer():
+    np.max(f(x, y))
 ```
 
 If you have a system monitor such as htop (Linux/Mac) or perfmon
@@ -198,7 +199,8 @@ np.max(f_vec(x, y))  # Run once to compile
 ```
 
 ```{code-cell} ipython3
-qe.timeit(lambda: np.max(f_vec(x, y)), runs=3)
+with qe.Timer():
+    np.max(f_vec(x, y))
 ```
 
 At least on our machine, the difference in the speed between the
@@ -248,7 +250,8 @@ np.max(f_vec(x, y))  # Run once to compile
 ```
 
 ```{code-cell} ipython3
-qe.timeit(lambda: np.max(f_vec(x, y)), runs=3)
+with qe.Timer():
+    np.max(f_vec(x, y))
 ```
 
 Now our code runs significantly faster than the NumPy version.

lectures/scipy.md

@@ -321,11 +321,13 @@ brentq(f, 0, 1)
 Here the correct solution is found and the speed is better than bisection:
 
 ```{code-cell} ipython
-qe.timeit(lambda: brentq(f, 0, 1), runs=3)
+with qe.Timer(unit="milliseconds"):
+    brentq(f, 0, 1)
 ```
 
 ```{code-cell} ipython
-qe.timeit(lambda: bisect(f, 0, 1), runs=3)
+with qe.Timer(unit="milliseconds"):
+    bisect(f, 0, 1)
 ```
 
 ### Multivariate Root-Finding