Update method name to match naming convention used elsewhere in the codebase.

Author: nirvdrum

src/main/java/org/truffleruby/core/rope/RopeOperations.java

@@ -136,7 +136,7 @@ public static Rope encodeAscii(String value, Encoding encoding) {
     }
 
     public static byte[] encodeAsciiBytes(String value) {
-        assert StringOperations.isASCIIOnly(value);
+        assert StringOperations.isAsciiOnly(value);
 
         final byte[] bytes = new byte[value.length()];
 

src/main/java/org/truffleruby/core/string/StringOperations.java

@@ -70,7 +70,7 @@ public static int clampExclusiveIndex(DynamicObject string, int index) {
     public static byte[] encodeBytes(String value, Encoding encoding) {
         // Taken from org.jruby.RubyString#encodeByteList.
 
-        if (encoding == ASCIIEncoding.INSTANCE && !isASCIIOnly(value)) {
+        if (encoding == ASCIIEncoding.INSTANCE && !isAsciiOnly(value)) {
             throw new UnsupportedOperationException(
                     StringUtils.format("Can't convert Java String (%s) to Ruby BINARY String because it contains non-ASCII characters", value));
         }
@@ -114,7 +114,7 @@ public static Encoding encoding(DynamicObject string) {
         return rope(string).getEncoding();
     }
 
-    public static boolean isASCIIOnly(String string) {
+    public static boolean isAsciiOnly(String string) {
         for (int i = 0; i < string.length(); i++) {
             int c = string.charAt(i);
             if (!Encoding.isAscii(c)) {

src/main/java/org/truffleruby/core/symbol/SymbolTable.java

@@ -79,7 +79,7 @@ public DynamicObject getSymbol(String string) {
         }
 
         final Rope rope;
-        if (StringOperations.isASCIIOnly(string)) {
+        if (StringOperations.isAsciiOnly(string)) {
             rope = RopeOperations.encodeAscii(string, USASCIIEncoding.INSTANCE);
         } else {
             rope = StringOperations.encodeRope(string, UTF8Encoding.INSTANCE);