Use StringBuilder::appendLiteral() / StringBuilder::append(char) when possible

Source/platform/text/LocaleWin.cpp

Index: Source/platform/text/LocaleWin.cpp
diff --git a/Source/platform/text/LocaleWin.cpp b/Source/platform/text/LocaleWin.cpp
index c658d02094f3af74efd2151a28ef84ba28d1994f..e4e56bcbcb2229ff1d4b396d5190714bb94df89e 100644
--- a/Source/platform/text/LocaleWin.cpp
+++ b/Source/platform/text/LocaleWin.cpp
@@ -304,9 +304,9 @@ static String convertWindowsDateTimeFormat(const String& format)
                 if (count <= 2)
                     converted.append(format, symbolStart, count);
                 else if (count == 3)
-                    converted.append("EEE");
+                    converted.appendLiteral("EEE");
                 else
-                    converted.append("EEEE");
+                    converted.appendLiteral("EEEE");
             } else if (ch == 'g') {
                 if (count == 1) {
                     converted.append('G');
@@ -452,7 +452,7 @@ String LocaleWin::shortTimeFormat()
         format = getLocaleInfoString(LOCALE_STIMEFORMAT);
         StringBuilder builder;
         builder.append(getLocaleInfoString(LOCALE_STIME));
-        builder.append("ss");
+        builder.appendLiteral("ss");
         size_t pos = format.reverseFind(builder.toString());
         if (pos != kNotFound)
             format.remove(pos, builder.length());