Support for GitGutter

[valkirilov]

About the Plugin: https://github.com/jisaacks/GitGutter
Demo: https://i.imgur.com/wYCNOdt.png

Added colors for the GitGutter markers:

<dict>
  <key>name</key>
  <string>GitGutter deleted</string>
  <key>scope</key>
  <string>markup.deleted.git_gutter</string>
  <key>settings</key>
  <dict>
    <key>foreground</key>
    <string>#F92672</string>
  </dict>
</dict>
<dict>
  <key>name</key>
  <string>GitGutter inserted</string>
  <key>scope</key>
  <string>markup.inserted.git_gutter</string>
  <key>settings</key>
  <dict>
    <key>foreground</key>
    <string>#A6E22E</string>
  </dict>
</dict>
<dict>
  <key>name</key>
  <string>GitGutter changed</string>
  <key>scope</key>
  <string>markup.changed.git_gutter</string>
  <key>settings</key>
  <dict>
    <key>foreground</key>
    <string>#967EFB</string>
  </dict>
</dict>
<dict>
  <key>name</key>
  <string>GitGutter ignored</string>
  <key>scope</key>
  <string>markup.ignored.git_gutter</string>
  <key>settings</key>
  <dict>
    <key>foreground</key>
    <string>#565656</string>
  </dict>
</dict>
<dict>
  <key>name</key>
  <string>GitGutter untracked</string>
  <key>scope</key>
  <string>markup.untracked.git_gutter</string>
  <key>settings</key>
  <dict>
    <key>foreground</key>
    <string>#565656</string>
  </dict>
</dict>

[kenwheeler]

Awesome, thanks!