Fix interpolated wrapper contains

Author: keith

syntax/swift.vim

@@ -52,10 +52,10 @@ delfunction s:CommentKeywordMatch
 
 " Literals
 " Strings
-syntax region swiftString start=/"/ skip=/\\\\\|\\"/ end=/"/ contains=swiftMultilineInterpolatedWrapper oneline
+syntax region swiftString start=/"/ skip=/\\\\\|\\"/ end=/"/ contains=swiftInterpolatedWrapper oneline
 syntax region swiftMultilineString start=/"""/ end=/"""/ contains=swiftMultilineInterpolatedWrapper
-syntax region swiftMultilineInterpolatedWrapper start="\v\\\(\s*" end="\v\s*\)" contained containedin=swiftMultilineString contains=swiftInterpolatedString oneline
-syntax region swiftInterpolatedWrapper start="\v[^\\]\zs\\\(\s*" end="\v\s*\)" contained containedin=swiftString contains=swiftInterpolatedString,swiftString oneline
+syntax region swiftMultilineInterpolatedWrapper start='\v\zs\\\(\s*' end='\v\s*\)' contained containedin=swiftMultilineString contains=swiftInterpolatedString oneline
+syntax region swiftInterpolatedWrapper start='\v(^|[^\\])\zs\\\(\s*' end='\v\s*\)' contained containedin=swiftString contains=swiftInterpolatedString,swiftString oneline
 syntax match swiftInterpolatedString "\v\w+(\(\))?" contained containedin=swiftInterpolatedWrapper,swiftMultilineInterpolatedWrapper oneline
 
 " Numbers