Address a couple issues in Khmer layout

bug: 6910993
Change-Id: I649b2d37a4eca75e2fc98e8c7f6a3dad20339864

java/res/xml/rowkeys_khmer1.xml

@@ -178,13 +178,15 @@
                  U+17A6: "ឦ" KHMER INDEPENDENT VOWEL QII -->
             <Key
                 latin:keyLabel="&#x17A5;"
-                latin:moreKeys=".,&#x17A6;"
+                latin:keyHintLabel="&#x17A6;"
+                latin:moreKeys=",&#x17A6;,."
                 latin:keyLabelFlags="fontNormal" />
             <!-- U+17B2: "ឲ" KHMER INDEPENDENT VOWEL QOO TYPE TWO
                  U+17B1: "ឱ" KHMER INDEPENDENT VOWEL QOO TYPE ONE -->
             <Key
                 latin:keyLabel="&#x17B2;"
-                latin:moreKeys="\\,,&#x17B1;"
+                latin:keyHintLabel="&#x17B1;"
+                latin:moreKeys="&#x17B1;,\\,"
                 latin:keyLabelFlags="fontNormal" />
         </default>
     </switch>

java/res/xml/rowkeys_khmer3.xml

@@ -39,7 +39,7 @@
                 latin:keyLabelFlags="fontNormal" />
             <!-- U+1792: "ធ" KHMER LETTER THO -->
             <Key
-                latin:keyLabel="&#x178C;"
+                latin:keyLabel="&#x1792;"
                 latin:keyLabelFlags="fontNormal" />
             <!-- U+17A2: "អ" KHMER LETTER QA -->
             <Key