Fix comment and add one more test

Author: davidwengier

src/Compiler/Microsoft.AspNetCore.Razor.Language/test/HtmlConventionsTest.cs

@@ -23,8 +23,8 @@ public static TheoryData<string, string> HtmlConversionData
                     { "CAPSOnOUTSIDE", "caps-on-outside" },
                     { "ALLCAPS", "allcaps" },
                     { "One1Two2Three3", "one1-two2-three3" },
-                    { "ONE1TWO2THREE3", "one1two2three3" },
                     { "First_Second_ThirdHi", "first_second_third-hi" },
+                    { "ONE1Two", "one1-two" },
                     { "One123Two234Three345", "one123-two234-three345" },
                     { "ONE123TWO234THREE345", "one123two234three345" },
                     { "1TWO2THREE3", "1two2three3" },

src/Compiler/Microsoft.CodeAnalysis.Razor.Compiler/src/Language/HtmlConventions.cs

@@ -109,7 +109,7 @@ private static bool ShouldInsertHyphenBeforeUppercase(ReadOnlySpan<char> input,
         if ((char.IsUpper(prev) || char.IsDigit(prev)) &&
             (i + 1 < input.Length) && char.IsLower(input[i + 1]))
         {
-            // Uppercase or digit followed by lowercase (e.g. CAPSOn → caps-on)
+            // Uppercase or digit followed by uppercase, followed by lowercase (e.g. CAPSOn → caps-on or ONE1Two → ONE1-Two)
             return true; ;
         }