Make tooltips more uniform

plugins/channelrx/demodfreedv/freedvdemodgui.ui

@@ -255,7 +255,7 @@
          </font>
         </property>
         <property name="toolTip">
-         <string>Channel power</string>
+         <string>Level meter (dB) top trace: average, bottom trace: instantaneous peak, tip: peak hold</string>
         </property>
        </widget>
       </item>

plugins/channeltx/filesource/filesourcegui.ui

@@ -541,7 +541,7 @@
       <item>
        <widget class="ButtonSwitch" name="playLoop">
         <property name="toolTip">
-         <string>Play in a loop</string>
+         <string>Play file in a loop</string>
         </property>
         <property name="text">
          <string/>

plugins/samplesource/fileinput/fileinputgui.ui

@@ -374,7 +374,7 @@
      <item>
       <widget class="ButtonSwitch" name="playLoop">
        <property name="toolTip">
-        <string>Play in a loop</string>
+        <string>Play file in a loop</string>
        </property>
        <property name="text">
         <string/>

sdrgui/gui/audiodialog.ui

@@ -184,7 +184,7 @@
             </size>
            </property>
            <property name="toolTip">
-            <string>Decimation</string>
+            <string>Decimation factor</string>
            </property>
            <item>
             <property name="text">