fix(blog): remove function (gnolang#2154)

<!-- please provide a detailed description of the changes made in this
pull request. -->

## Description

This PR adds better removing to the blog `Remove` function.

<details><summary>Contributors' checklist...</summary>

- [x] Added new tests, or not needed, or not feasible
- [x] Provided an example (e.g. screenshot) to aid review or the PR is
self-explanatory
- [x] Updated the official documentation or not needed
- [x] No breaking changes were made, or a `BREAKING CHANGE: xxx` message
was included in the description
- [x] Added references to related issues and PRs
- [ ] Provided any useful hints for running manual tests
- [ ] Added new benchmarks to [generated
graphs](https://gnoland.github.io/benchmarks), if any. More info
[here](https://github.com/gnolang/gno/blob/master/.benchmarks/README.md).
</details>

examples/gno.land/p/demo/blog/blog.gno

@@ -175,8 +175,8 @@ func (b *Blog) prepareAndSetPost(post *Post) error {
 	post.Blog = b
 	post.UpdatedAt = time.Now()
 
-	trimmedTitleKey := strings.Replace(post.Title, " ", "", -1)
-	pubDateKey := post.CreatedAt.Format(time.RFC3339)
+	trimmedTitleKey := getTitleKey(post.Title)
+	pubDateKey := getPublishedKey(post.CreatedAt)
 
 	// Cannot have two posts with same title key
 	if _, found := b.PostsAlphabetical.Get(trimmedTitleKey); found {
@@ -196,14 +196,19 @@ func (b *Blog) prepareAndSetPost(post *Post) error {
 }
 
 func (b *Blog) RemovePost(slug string) {
-	_, exists := b.Posts.Get(slug)
+	p, exists := b.Posts.Get(slug)
 	if !exists {
-		panic("post with specified slug does not exist")
+		panic("post with specified slug doesn't exist")
 	}
 
+	post := p.(*Post)
+
+	titleKey := getTitleKey(post.Title)
+	publishedKey := getPublishedKey(post.CreatedAt)
+
 	_, _ = b.Posts.Remove(slug)
-	_, _ = b.PostsAlphabetical.Remove(slug)
-	_, _ = b.PostsPublished.Remove(slug)
+	_, _ = b.PostsAlphabetical.Remove(titleKey)
+	_, _ = b.PostsPublished.Remove(publishedKey)
 }
 
 func (b *Blog) GetPost(slug string) *Post {

examples/gno.land/p/demo/blog/util.gno

@@ -1,7 +1,18 @@
 package blog
 
-import "strings"
+import (
+	"strings"
+	"time"
+)
 
 func breadcrumb(parts []string) string {
 	return "# " + strings.Join(parts, " / ") + "\n\n"
 }
+
+func getTitleKey(title string) string {
+	return strings.Replace(title, " ", "", -1)
+}
+
+func getPublishedKey(t time.Time) string {
+	return t.Format(time.RFC3339)
+}

examples/gno.land/r/gnoland/blog/gnoblog_test.gno

@@ -166,18 +166,32 @@ Published by g1u7y667z64x2h7vc6fmpcprgey4ck233jaww9zq to Gnoland's Blog
 	}
 
 	{ // Test remove functionality
-		ModAddPost("testSlug1", "testTitle1", "body1", "2022-05-22T13:17:22Z", "moul", "tag1,tag2")
+		title := "example title"
+		slug := "testSlug1"
+		ModAddPost(slug, title, "body1", "2022-05-25T13:17:22Z", "moul", "tag1,tag2")
 
-		got := Render("p/testSlug1")
+		got := Render("")
+
+		if !strings.Contains(got, title) {
+			t.Errorf("post was not added properly")
+		}
+
+		postRender := Render("p/" + slug)
+
+		if !strings.Contains(postRender, title) {
+			t.Errorf("post not rendered properly")
+		}
+
+		ModRemovePost(slug)
+		got = Render("")
 
-		if got == "404" {
-			t.Errorf("did not expect 404")
+		if strings.Contains(got, title) {
+			t.Errorf("post was not removed")
 		}
 
-		ModRemovePost("testSlug1")
-		got = Render("p/testSlug1")
+		postRender = Render("p/" + slug)
 
-		assertMDEquals(t, got, "404")
+		assertMDEquals(t, postRender, "404")
 	}
 
 	// TODO: pagination.