wxGUI/sqlbuilder: add tooltip for sample btn

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@54256 15284696-431f-4ddb-bdfa-cd5b030d7da7

gui/wxpython/dbmgr/sqlbuilder.py

@@ -201,6 +201,7 @@ class SQLBuilder(wx.Frame):
         self.btn_unique.Enable(False)
         self.btn_uniquesample = wx.Button(parent = self.valuespanel, id = wx.ID_ANY,
                                           label = _("Get sample"))
+        self.btn_uniquesample.SetToolTipString(_("Get first 256 unique values as sample"))
         self.btn_uniquesample.Enable(False)
 
         buttonsizer3 = wx.BoxSizer(wx.HORIZONTAL)