rename Lexer folder to match namespace, some cleanups and color adjustments

src/UI/CSConsole/Lexers/NumberLexer.cs

@@ -0,0 +1,32 @@
+using UnityEngine;
+
+namespace UnityExplorer.UI.CSharpConsole.Lexers
+{
+    public class NumberLexer : Lexer
+    {
+        // Maroon
+        protected override Color HighlightColor => new Color(0.58f, 0.33f, 0.33f, 1.0f);
+
+        private bool IsNumeric(char c) => char.IsNumber(c) || c == '.';
+
+        public override bool TryMatchCurrent(LexerBuilder lexer)
+        {
+            // previous character must be whitespace or delimiter
+            if (!lexer.IsDelimiter(lexer.Previous, true))
+                return false;
+
+            if (!IsNumeric(lexer.Current))
+                return false;
+
+            while (!lexer.EndOfInput)
+            {
+                lexer.Commit();
+                if (!IsNumeric(lexer.PeekNext()))
+                    break;
+            }
+
+            return true;
+        }
+    }
+
+}