Highlight label after break/continue (#351)

Fixes #159.

Author: rhysd

syntax/rust.vim

@@ -205,6 +205,7 @@ syn region rustGenericLifetimeCandidate display start=/\%(<\|,\s*\)\@<='/ end=/[
 "rustLifetime must appear before rustCharacter, or chars will get the lifetime highlighting
 syn match     rustLifetime    display "\'\%([^[:cntrl:][:space:][:punct:][:digit:]]\|_\)\%([^[:cntrl:][:punct:][:space:]]\|_\)*"
 syn match     rustLabel       display "\'\%([^[:cntrl:][:space:][:punct:][:digit:]]\|_\)\%([^[:cntrl:][:punct:][:space:]]\|_\)*:"
+syn match     rustLabel       display "\%(\<\%(break\|continue\)\s*\)\@<=\'\%([^[:cntrl:][:space:][:punct:][:digit:]]\|_\)\%([^[:cntrl:][:punct:][:space:]]\|_\)*"
 syn match   rustCharacterInvalid   display contained /b\?'\zs[\n\r\t']\ze'/
 " The groups negated here add up to 0-255 but nothing else (they do not seem to go beyond ASCII).
 syn match   rustCharacterInvalidUnicode   display contained /b'\zs[^[:cntrl:][:graph:][:alnum:][:space:]]\ze'/