ParseFirstComponent(): Remove unnecesary mutation of rp

This method doesn't take a pointer receiver, so mutating rp.path is
pointless.

Author: EdSchouten

pkg/filesystem/path/unix_parser.go

@@ -64,8 +64,9 @@ func (rp unixRelativeParser) ParseFirstComponent(componentWalker ComponentWalker
 		remainder = nil
 	} else {
 		name = rp.path[:slash]
-		rp.path = stripUNIXSeparators(rp.path[slash:])
-		remainder = unixRelativeParser{rp.path}
+		remainder = unixRelativeParser{
+			path: stripUNIXSeparators(rp.path[slash:]),
+		}
 	}
 
 	switch name {

pkg/filesystem/path/windows_parser.go

@@ -66,8 +66,9 @@ func (rp windowsRelativeParser) ParseFirstComponent(componentWalker ComponentWal
 		remainder = nil
 	} else {
 		name = rp.path[:separator]
-		rp.path = stripWindowsSeparators(rp.path[separator:])
-		remainder = windowsRelativeParser{rp.path}
+		remainder = windowsRelativeParser{
+			path: stripWindowsSeparators(rp.path[separator:]),
+		}
 	}
 
 	switch name {