fix readme messing title

subjects/btreeapplyinorder.en.md

@@ -1,4 +1,4 @@
-## btreeinsertdata
+## btreeapplyinorder
 
 ### Instructions
 

subjects/btreeapplypostorder.en.md

@@ -1,4 +1,4 @@
-## btreeinsertdata
+## btreeapplypostorder
 
 ### Instructions
 

subjects/btreeapplypreorder.en.md

@@ -1,4 +1,4 @@
-## btreeinsertdata
+## btreeapplypreorder
 
 ### Instructions
 

subjects/btreeisbinary.en.md

@@ -2,7 +2,7 @@
 
 ### Instructions
 
-Write a function, BTreeIsBinary, that returns true only if the tree given by root follows the binary search tree properties.
+Write a function, `BTreeIsBinary`, that returns true only if the tree given by root follows the binary search tree properties.
 
 This function must have the following signature.
 

subjects/btreelevelcount.en.md

@@ -2,7 +2,7 @@
 
 ### Instructions
 
-Write a function, BTreeLevelCount, that return the number of levels of the tree (height of the tree)
+Write a function, `BTreeLevelCount`, that return the number of levels of the tree (height of the tree)
 
 ### Expected function
 

subjects/btreesearchitem.en.md

@@ -1,4 +1,4 @@
-## btreeinsertdata
+## btreesearchitem
 
 ### Instructions