Panic using fmt on filesystem path that does not exist

[relvacode]

$ templ fmt "this path does not exist"

panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x18 pc=0xefe7626]

goroutine 36 [running]:
github.com/a-h/templ/cmd/templ/processor.Process.func1.FindTemplates.1({0x7ff7b21e99a2, 0x18}, {0x0, 0x0}, {0x0?, 0x0?})
        /Users/jkingsbury/go/pkg/mod/github.com/a-h/templ@v0.2.598/cmd/templ/processor/processor.go:46 +0x26
path/filepath.Walk({0x7ff7b21e99a2, 0x18}, 0xc000216fb8)
        /Users/jkingsbury/go/pkg/mod/golang.org/toolchain@v0.0.1-go1.22.0.darwin-amd64/src/path/filepath/path.go:558 +0x4a
github.com/a-h/templ/cmd/templ/processor.FindTemplates(...)
        /Users/jkingsbury/go/pkg/mod/github.com/a-h/templ@v0.2.598/cmd/templ/processor/processor.go:45
github.com/a-h/templ/cmd/templ/processor.Process.func1()
        /Users/jkingsbury/go/pkg/mod/github.com/a-h/templ@v0.2.598/cmd/templ/processor/processor.go:22 +0x7a
created by github.com/a-h/templ/cmd/templ/processor.Process in goroutine 35
        /Users/jkingsbury/go/pkg/mod/github.com/a-h/templ@v0.2.598/cmd/templ/processor/processor.go:20 +0xa7