Click Preferences -> Browse Packages...to find configuration files.
The label is specified in HTML / Comments.tmPreferences. You can modify this file to change the comments of all jsp and html files .
jsp, JavaServerPagesComments.tmPreferences /Java :
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>name</key>
<string>Comments</string>
<key>scope</key>
<string>text.html.jsp</string>
<key>settings</key>
<dict>
<key>shellVariables</key>
<array>
<dict>
<key>name</key>
<string>TM_COMMENT_START</string>
<key>value</key>
<string><%-- </string>
</dict>
<dict>
<key>name</key>
<string>TM_COMMENT_END</string>
<key>value</key>
<string> --%></string>
</dict>
</array>
</dict>
<key>uuid</key>
<string>54444C7B-54D2-41F6-A817-AEE243C3D45A</string>
</dict>
</plist>