gopages: Encode page URLs instead of failable decoding (JohnStarich#8)

Fix an issue where paths that couldn't be URL decoded were failing to parse and panicking.

We don't even need to parse URLs in this scenario, so remove the error path entirely.

Fix JohnStarich#7

gopages/internal/generate/generate.go

@@ -217,10 +217,7 @@ func doRequest(do func(w http.ResponseWriter)) ([]byte, error) {
 }
 
 func getPage(pres *godoc.Presentation, path string) ([]byte, error) {
-	u, err := url.Parse(path)
-	if err != nil {
-		panic(err)
-	}
+	u := &url.URL{Path: path}
 	return doRequest(func(w http.ResponseWriter) {
 		pres.ServeHTTP(w, &http.Request{URL: u})
 	})

gopages/internal/generate/generate_test.go

@@ -58,6 +58,7 @@ package mylib
 `)
 	writeFile(".git/something", `ignored dot dir`)
 	writeFile(".dotfile", `ignored dot file`)
+	writeFile("%name.PascalCased%/other.go", `package bad_url_decode`)
 
 	args := flags.Args{}
 	const modulePackage = "github.com/my/thing"
@@ -71,13 +72,16 @@ package mylib
 		"index.html",
 		"pkg/github.com/index.html",
 		"pkg/github.com/my/index.html",
+		"pkg/github.com/my/thing/%name.PascalCased%/index.html", // Verifies fix for https://github.com/JohnStarich/go/issues/7
 		"pkg/github.com/my/thing/index.html",
 		"pkg/github.com/my/thing/internal/hello/index.html",
 		"pkg/github.com/my/thing/internal/index.html",
 		"pkg/github.com/my/thing/mylib/index.html",
 		"pkg/index.html",
 		"src/github.com/index.html",
 		"src/github.com/my/index.html",
+		"src/github.com/my/thing/%name.PascalCased%/index.html",
+		"src/github.com/my/thing/%name.PascalCased%/other.go.html",
 		"src/github.com/my/thing/index.html",
 		"src/github.com/my/thing/internal/hello/hello.go.html",
 		"src/github.com/my/thing/internal/hello/index.html",