Add back-slash key

This change also moves some keys,

- Infinite is moved to popup char of plus-minus.
- not-equal and nearly-equal are moved to popup chars of equal.

Bug: 3224679
Change-Id: I7c95ab5a7cd78e4dae13fb511edad607dcaed8da

java/res/xml-xlarge/kbd_symbols.xml

@@ -139,7 +139,9 @@
         <Key
             latin:keyLabel="]" />
         <Key
-            latin:keyLabel="=" />
+            latin:keyLabel="="
+            latin:popupKeyboard="@xml/kbd_popup_template"
+            latin:popupCharacters="≠≈" />
         <Key
             latin:keyLabel=":" />
         <Key

java/res/xml-xlarge/kbd_symbols_shift.xml

@@ -85,11 +85,13 @@
             latin:popupKeyboard="@xml/kbd_popup_template"
             latin:popupCharacters="↑↓←→" />
         <Key
-            latin:keyLabel="∞"
+            latin:keyLabel="°"
             latin:popupKeyboard="@xml/kbd_popup_template"
-            latin:popupCharacters="≠≈" />
+            latin:popupCharacters="¶§" />
         <Key
-            latin:keyLabel="±" />
+            latin:keyLabel="±"
+            latin:popupKeyboard="@xml/kbd_popup_template"
+            latin:popupCharacters="∞" />
         <Key
             latin:keyLabel="[" />
         <Key
@@ -106,6 +108,8 @@
             latin:keyStyle="moreKeyStyle"
             latin:keyWidth="15.192%p"
             latin:keyEdgeFlags="left" />
+        <Key
+            latin:keyLabel="\\" />
         <Key
             latin:keyLabel="©" />
         <Key
@@ -116,10 +120,6 @@
             latin:keyLabel="{" />
         <Key
             latin:keyLabel="}" />
-        <Key
-            latin:keyLabel="°"
-            latin:popupKeyboard="@xml/kbd_popup_template"
-            latin:popupCharacters="¶§" />
         <Key
             latin:keyLabel="," />
         <Key