It is not fixed as it is no bug. According to the history of Ruby constants have never been part of the symbol index out of the box.
It’s always a question of taste to decide how much to add to the index. Adding too much may also cause too much noise.
You don’t need to manipulate the existing symbol definition, but easily extend the default behavior by writing your own symbol definition.
Packages/User/Ruby/Symbols - Constants.tmPreferences
<?xml version="1.0" encoding="UTF-8"?>
<plist version="1.0">
<dict>
<key>scope</key>
<string>source.ruby entity.name.constant</string>
<key>settings</key>
<dict>
<key>showInSymbolList</key>
<integer>1</integer>
<key>showInIndexedSymbolList</key>
<integer>1</integer>
</dict>
</dict>
</plist>
Nevertheless, any kind of improvement to the default syntaxes is very welcome. You’ll find the repo of ST’s builtin syntax packages at https://github.com/sublimehq/Packages. It is the place to discuss issues, ideas and propose changes.
Development of ST’s default syntaxes takes place as an Open Source approach mainly driven by the community. The final review and decision is up to @wbond (or any other core developer) then.