Fix crash on interpreter parsing

CHANGELOG.md

@@ -7,6 +7,7 @@ Change Log
 
 ### Fixes
 - Fix an issue where items in the Script menu were not sorted by prefix numbers.
+- Fix a possible crash on handling documents with an invalid shebang.
 
 
 

CotEditor/Sources/SyntaxManager.swift

@@ -565,7 +565,7 @@ private extension String {
         
         // use first arg if the path targets env
         if interpreter == "env" {
-            return components[1]
+            return components[safe: 1]
         }
         
         return interpreter