Fixed a Typo in Substrings

strings/substrings.md

@@ -1,28 +1,32 @@
 # Substrings
 
-substring is used to take a part of a string.
-Syntax:  substring(first_index,last_index).
+Substring is used to take a part of a string.
+Syntax: substring(first_index,last_index).
 
 ```js
-var a = 'Hello world!';
-document.write(a.substring(1,6));
+var a = "Hello world!";
+document.write(a.substring(1, 6));
 ```
-The preceding code snippet gives ```'ello '``` . Note that the 'w' (index 6) is not part of this substring.
+
+The preceding code snippet gives `'ello '` . Note that the 'w' (index 6) is not part of this substring.
 
 We could also do,
+
 ```js
-var a = 'Hello world!';
+var a = "Hello world!";
 document.write(a.substring(2));
 ```
-This gives the whole string from the character with index 2. ``` 'llo world!'```
+
+This gives the whole string from the character with index 2. `'llo world!'`
 
 ##substr
 
 There is also a method substr() that works slightly differently. Instead of the second number being an index number,
 it gives the number of characters.
+
 ```js
-var a = 'Hello world!';
-document.write(a.substr(1,6));
+var a = "Hello world!";
+document.write(a.substr(1, 6));
 ```
 
-starts at the character with index 1 ('e') and then gives 6 characters, so the output is ```ello w```
+starts at the character with index 1 ('e') and then gives 6 characters, so the output is `ello w`