[mix-messy-graph] Fix content title

Author: woojiahao

mix_messy_graph/tests/specs/branches_not_deleted.yml

@@ -37,7 +37,7 @@ initialization:
       contents: |
         # Features
 
-        ## Create Book
+        ## Creating Book
 
         Allows creating one book at a time.
 

mix_messy_graph/tests/specs/features_content_invalid.yml

@@ -31,7 +31,7 @@ initialization:
         Allows searching for books by keywords.
         Works only for book titles.
 
-        ## Create Book
+        ## Creating Book
 
         Allows creating one book at a time.
 

mix_messy_graph/tests/specs/missing_commit.yml

@@ -22,7 +22,7 @@ initialization:
       contents: |
         # Features
 
-        ## Create Book
+        ## Creating Book
 
         Allows creating one book at a time.
 

mix_messy_graph/tests/specs/non_squash_merge_used.yml

@@ -32,7 +32,7 @@ initialization:
       contents: |
         # Features
 
-        ## Create Book
+        ## Creating Book
 
         Allows creating one book at a time.
 

mix_messy_graph/tests/specs/non_squash_merge_used_2.yml

@@ -33,7 +33,7 @@ initialization:
       contents: |
         # Features
 
-        ## Create Book
+        ## Creating Book
 
         Allows creating one book at a time.
 

mix_messy_graph/tests/specs/wrong_commit_message.yml

@@ -26,7 +26,7 @@ initialization:
       contents: |
         # Features
 
-        ## Create Book
+        ## Creating Book
 
         Allows creating one book at a time.
 

mix_messy_graph/verify.py

@@ -36,7 +36,7 @@
 
 EXPECTED_LINES = [
     "# Features",
-    "## Create Book",
+    "## Creating Book",
     "Allows creating one book at a time.",
     "## Searching for Books",
     "Allows searching for books by keywords.",