De-duplicate the word 'a' in intro to Installing Kotlin page (#374)

* De-duplicate the word 'a' in intro to Installing Kotlin page
* Fix typo in the word "programming"

Co-authored-by: Danny Diaz <[email protected]>

Author: rowan-mcalpin

docs/source/programming_resources/shared/installing_kotlin/Installing-Kotlin.rst

@@ -6,7 +6,7 @@ What Is Kotlin?
 ---------------
 
 
-The Kotlin programming language is a a modern alternative to the Java programing language
+The Kotlin programming language is a modern alternative to the Java programming language
 that compiles and runs on the Java Virtual Machine (JVM) and can be used to develop Android
 applications. It was developed by JetBrains, the same company that developed the IntelliJ IDE
 (the basis for Android Studio).