L10N: Don't translate strings that dont contain any alphabetic character

Per 0penBrain's suggestion

src/Mod/TechDraw/Gui/DlgPrefsTechDrawDimensions.ui

@@ -407,7 +407,7 @@ Multiplier of 'Font Size'</string>
            <string>Character used to indicate diameter dimensions</string>
           </property>
           <property name="text">
-           <string>⌀</string>
+           <string notr="true">⌀</string>
           </property>
           <property name="alignment">
            <set>Qt::AlignRight|Qt::AlignTrailing|Qt::AlignVCenter</set>

src/Mod/TechDraw/Gui/TaskProjGroup.ui

@@ -133,7 +133,7 @@
      <item>
       <widget class="QLabel" name="label_4">
        <property name="text">
-        <string>:</string>
+        <string notr="true">:</string>
        </property>
       </widget>
      </item>

src/Mod/TechDraw/Gui/TaskRestoreLines.ui

@@ -26,7 +26,7 @@
      <item row="0" column="1">
       <widget class="QLabel" name="l_All">
        <property name="text">
-        <string>0</string>
+        <string notr="true">0</string>
        </property>
        <property name="alignment">
         <set>Qt::AlignCenter</set>
@@ -43,7 +43,7 @@
      <item row="1" column="1">
       <widget class="QLabel" name="l_Geometry">
        <property name="text">
-        <string>0</string>
+        <string notr="true">0</string>
        </property>
        <property name="alignment">
         <set>Qt::AlignCenter</set>
@@ -60,7 +60,7 @@
      <item row="2" column="1">
       <widget class="QLabel" name="l_Cosmetic">
        <property name="text">
-        <string>0</string>
+        <string notr="true">0</string>
        </property>
        <property name="alignment">
         <set>Qt::AlignCenter</set>
@@ -77,7 +77,7 @@
      <item row="3" column="1">
       <widget class="QLabel" name="l_Center">
        <property name="text">
-        <string>0</string>
+        <string notr="true">0</string>
        </property>
        <property name="alignment">
         <set>Qt::AlignCenter</set>

src/Mod/TechDraw/Gui/TaskSurfaceFinishSymbols.ui

@@ -105,7 +105,7 @@
         <string>&lt;html&gt;&lt;head/&gt;&lt;body&gt;&lt;p&gt;Rotation angle&lt;/p&gt;&lt;/body&gt;&lt;/html&gt;</string>
        </property>
        <property name="text">
-        <string>0</string>
+        <string notr="true">0</string>
        </property>
       </widget>
      </item>