fix: simplify Windows path handling to match

  spec

Author: mertcanaltin

lib/url-state-machine.js

@@ -575,16 +575,18 @@ URLStateMachine.prototype["parse scheme start"] = function parseSchemeStart(c, c
 URLStateMachine.prototype["parse scheme"] = function parseScheme(c, cStr) {
   if (infra.isASCIIAlphanumeric(c) || c === p("+") || c === p("-") || c === p(".")) {
     this.buffer += cStr.toLowerCase();
-  } else if (c === p(":") && countSymbols(this.buffer) === 1 &&
-             infra.isASCIIAlpha(this.buffer.codePointAt(0)) &&
-             this.input[this.pointer + 1] === p("\\")) {
-    this.url.scheme = "file";
-    this.url.host = "";
-    // Preserve original case from input (buffer was lowercased in scheme start)
-    const originalDriveLetter = String.fromCodePoint(this.input[this.pointer - 1]);
-    this.buffer = `${originalDriveLetter}:`;
-    this.state = "path";
   } else if (c === p(":")) {
+    // Windows drive letter handling
+    if (this.buffer.length === 1 && infra.isASCIIAlpha(this.buffer.codePointAt(0)) &&
+        this.input[this.pointer + 1] === p("\\") && !this.stateOverride) {
+      this.url.scheme = "file";
+      this.url.host = "";
+      // Preserve the original case of the drive letter from input
+      const driveLetter = String.fromCodePoint(this.input[this.pointer - 1]);
+      this.buffer = `${driveLetter}:`;
+      this.state = "path";
+      return true;
+    }
     if (this.stateOverride) {
       if (isSpecial(this.url) && !isSpecialScheme(this.buffer)) {
         return false;