message: Fix highlighting of {\{...\}} blocks
  Make sure the right paren in \} does not match the first opening {.
  This closes
diff: <array>
  <dict>
  <key>begin</key>
  - <string>\{</string>
  + <string>(?<!\\)\{</string>
  <key>beginCaptures</key>
  <dict>
  <key>0</key>
  </dict>
  </dict>
  <key>end</key>
  - <string>\}</string>
  + <string>(?<!\\)\}</string>
  <key>endCaptures</key>
  <dict>
  <key>0</key>
  </dict>
  </dict>
  <key>match</key>
  - <string>(\\)([^a-zA-Z]|[A-Za-z]+)(?=\b|\}|\]|\^|\_)</string>
  + <string>(\\)([^a-zA-Z]|[A-Za-z]+)(?=\b|\s|\}|\]|\^|\_|\\)</string>
  <key>name</key>
  <string>constant.other.general.math.tex</string>
  </dict>
  