Add Nextflow language support (#3870)

* Added nextflow language
* Added main.nf to list of filenames
* Fixed duplicate groovy scope
* Removed hello-world example
* Update grammar submodule
* Removed main.nf from filenames
* Added nextflow.config example

lib/linguist/languages.yml

@@ -2905,6 +2905,18 @@ NewLisp:
   codemirror_mode: commonlisp
   codemirror_mime_type: text/x-common-lisp
   language_id: 247
+Nextflow:
+  type: programming
+  ace_mode: groovy
+  tm_scope: source.nextflow
+  color: "#3ac486"
+  extensions:
+  - ".nf"
+  filenames:
+  - "nextflow.config"  
+  interpreters:
+  - nextflow
+  language_id: 506780613
 Nginx:
   type: data
   extensions: