fix(curriculum): standardize fill-in-the-blank format and typos (#39011)

This PR changes the format of earlier fill-in-the-blank questions/answers to the one used in later questions. It also fixes a few typos.

curriculum/challenges/english/11-machine-learning-with-python/tensorflow/creating-a-convolutional-neural-network.english.md

@@ -16,7 +16,7 @@ videoId: kfv0K8MtkIc
 ```yml
 question:
   text: |
-    Fill in the blanks below to complete the architechture for a convolutional neural network:
+    Fill in the blanks below to complete the architecture for a convolutional neural network:
 
     ```py
     model = models.__A__()

curriculum/challenges/english/11-machine-learning-with-python/tensorflow/natural-language-processing-with-rnns-create-a-play-generator.english.md

@@ -16,7 +16,6 @@ videoId: j5xsxjq_Xk8
 ```yml
 question:
   text: |
-
     Fill in the blanks below to create the training examples for the RNN:
 
     ```py

curriculum/challenges/english/11-machine-learning-with-python/tensorflow/natural-language-processing-with-rnns.english.md

@@ -16,7 +16,7 @@ videoId: ZyCaF5S-lKg
 ```yml
 question:
   text: |
-    Natural Language Processing is a branch of artifitial intelligence that...:
+    Natural Language Processing is a branch of artificial intelligence that...:
   answers:
     - deals with how computers understand and process natural/human languages.
     - translates image data into natural/human languages.

curriculum/challenges/english/11-machine-learning-with-python/tensorflow/neural-networks-optimizers.english.md

@@ -18,7 +18,7 @@ question:
   text: What is an optimizer function?
   answers:
     - A function that increases the accuracy of a model's predictions.
-    - A function that implements the gradient descent and backpropogation algorithms for you.
+    - A function that implements the gradient descent and backpropagation algorithms for you.
     - A function that reduces the time a model needs to train.
   solution: 2
 ```