Fix one more problem.

strmangle/strmangle.go

@@ -205,8 +205,12 @@ func TitleCase(n string) string {
 				}
 			}
 		} else {
-			buf.WriteByte(word[0] - 32)
+			if c := word[0]; c > 96 && c < 123 {
-			buf.Write(word[1:])
+				buf.WriteByte(word[0] - 32)
+				buf.Write(word[1:])
+			} else {
+				buf.Write(word)
+			}
 		}
 
 		start = end + 1

strmangle/strmangle_test.go

@@ -177,6 +177,7 @@ func TestTitleCase(t *testing.T) {
 		{"zxc_vdf0c0_hello0", "ZXCVDF0C0Hello0"},
 		{"id0_uid000_guid0e0", "ID0UID000GUID0E0"},
 		{"ab_5zxc5d5", "Ab5ZXC5D5"},
+		{"Identifier", "Identifier"},
 	}
 
 	for i, test := range tests {