syntax: Stop highlighting character following closing """

Backport from vim/vim#1553

Author: ches

syntax/scala.vim

@@ -146,7 +146,7 @@ hi link scalaString String
 hi link scalaStringEmbeddedQuote String
 
 syn region scalaIString matchgroup=scalaInterpolationBrackets start=/\<[a-zA-Z][a-zA-Z0-9_]*"/ skip=/\\"/ end=/"/ contains=scalaInterpolation,scalaInterpolationB,scalaEscapedChar,scalaUnicodeChar
-syn region scalaTripleIString matchgroup=scalaInterpolationBrackets start=/\<[a-zA-Z][a-zA-Z0-9_]*"""/ end=/"""\%([^"]\|$\)/ contains=scalaInterpolation,scalaInterpolationB,scalaEscapedChar,scalaUnicodeChar
+syn region scalaTripleIString matchgroup=scalaInterpolationBrackets start=/\<[a-zA-Z][a-zA-Z0-9_]*"""/ end=/"""\ze\%([^"]\|$\)/ contains=scalaInterpolation,scalaInterpolationB,scalaEscapedChar,scalaUnicodeChar
 hi link scalaIString String
 hi link scalaTripleIString String