Improve forc doc navigation interface (FuelLabs#4212)

## Description

Changes the path to the root when clicking the Sway logo. Adds some nice
CSS for the button that navigates to the `all doc`, and adds links to
each parent module in a `CallPath`.

[Screencast from 2023-03-07
17-20-16.webm](https://user-images.githubusercontent.com/57543709/223628980-855d29dd-029f-440e-89e2-96f8484741a9.webm)



## Checklist

- [x] I have linked to any relevant issues. 
    Closes FuelLabs#3996 
    Closes FuelLabs#4195 
    Closes FuelLabs#4197 
    Closes FuelLabs#4196 
- [x] I have commented my code, particularly in hard-to-understand
areas.
- [x] I have updated the documentation where relevant (API docs, the
reference, and the Sway book).
- [x] I have added tests that prove my fix is effective or that my
feature works.
- [x] I have added (or requested a maintainer to add) the necessary
`Breaking*` or `New Feature` labels where relevant.
- [x] I have done my best to ensure that my PR adheres to [the Fuel Labs
Code Review
Standards](https://github.com/FuelLabs/rfcs/blob/master/text/code-standards/external-contributors.md).
- [x] I have requested a review from the relevant team or maintainers.

forc-plugins/forc-doc/src/assets/ayu.css

@@ -169,9 +169,6 @@ pre,
 .content a.macro {
   color: #a37acc;
 }
-.sidebar a {
-  color: #53b1db;
-}
 .sidebar a.current.type {
   color: #53b1db;
 }
@@ -192,7 +189,7 @@ nav.main .separator {
   border: 1px solid #5c6773;
 }
 a {
-  color: #39afd7;
+    color: #c5c5c5;
 }
 .sidebar h2 a,
 .sidebar h3 a {
@@ -487,3 +484,11 @@ details.dir-entry summary:focus {
 .toggle-line:hover .toggle-line-inner {
   background: #c5c5c5;
 }
+.sidebar .location {
+  border-color: #000;
+  background-color: #0f1419;
+  color: #fff;
+}
+#all-types {
+  background-color: #14191f;
+}

forc-plugins/forc-doc/src/assets/swaydoc.css

@@ -82,7 +82,7 @@ html {
   }
 }
 body {
-  font: 1rem/1.5 "Source Serif 4", NanumBarunGothic, serif;
+  font: 16px/1.4 "Source Serif 4", NanumBarunGothic, serif;
   margin: 0;
   position: relative;
   overflow-wrap: break-word;
@@ -249,7 +249,7 @@ ol ol {
   margin-bottom: 0.625em;
 }
 p {
-  margin: 0 0 0.75em 0;
+    margin: 0 0 .6em 0;
 }
 summary {
   outline: none;
@@ -363,20 +363,25 @@ nav.sub {
 }
 .sidebar {
   font-size: 0.875rem;
-  width: 250px;
+  width: 200px;
   min-width: 200px;
   overflow-y: scroll;
   position: sticky;
   height: 100vh;
   top: 0;
   left: 0;
 }
-.sidebar-elems,
 .sidebar > .location {
   padding-left: 24px;
 }
 .sidebar .location {
-  overflow-wrap: anywhere;
+    border: 1px solid;
+    font-size: 17px;
+    margin: 30px 10px 20px 10px;
+    text-align: center;
+    word-wrap: break-word;
+    font-weight: inherit;
+    padding: 0;
 }
 .swaydoc.source .sidebar {
   width: 50px;
@@ -413,7 +418,17 @@ nav.sub {
   visibility: visible;
 }
 #all-types {
-  margin-top: 1em;
+  text-align: center;
+  border: 1px solid;
+  margin: 0 10px;
+  margin-bottom: 10px;
+  display: block;
+  border-radius: 7px;
+}
+a#all-types:hover,
+a#all-types:active {
+  background-color: var(--sidebar-background-color-hover);
+  color: #c5c5c5;
 }
 * {
   scrollbar-width: initial;
@@ -475,7 +490,7 @@ nav.sub {
 h2.location a {
   display: block;
   padding: 0.25rem;
-  margin-left: -0.25rem;
+  margin-left: 2em;
   text-overflow: ellipsis;
   overflow: hidden;
 }
@@ -1994,3 +2009,6 @@ details.swaydoc-toggle[open] > summary.hideme::after {
 .example-links ul {
   margin-bottom: 0;
 }
+#all-types>p {
+    margin: 5px 0;
+}

forc-plugins/forc-doc/src/doc.rs

@@ -1,10 +1,13 @@
 use crate::{
     descriptor::Descriptor,
-    render::{split_at_markdown_header, DocLink, DocStrings, ItemBody, ItemHeader, Renderable},
+    render::{
+        split_at_markdown_header, DocLink, DocStrings, ItemBody, ItemHeader, Renderable,
+        INDEX_FILENAME,
+    },
     RenderPlan,
 };
 use anyhow::Result;
-use horrorshow::{box_html, RenderBox};
+use horrorshow::{box_html, RenderBox, Template};
 use std::{fmt::Write, option::Option, path::PathBuf};
 use sway_core::{
     decl_engine::DeclEngine,
@@ -215,6 +218,27 @@ impl ModuleInfo {
         }
         iter.map(|s| s.as_str()).collect::<Vec<&str>>().join("::")
     }
+    /// Renders the [ModuleInfo] into a [CallPath] with anchors. We return this as a `Result<Vec<String>>`
+    /// since the `box_html!` macro returns a closure and no two closures are considered the same type.
+    pub(crate) fn get_anchors(&self) -> Result<Vec<String>> {
+        let mut count = self.depth();
+        let mut rendered_module_anchors = Vec::with_capacity(self.depth());
+        for prefix in self.module_prefixes.iter() {
+            let mut href = (1..count).map(|_| "../").collect::<String>();
+            href.push_str(INDEX_FILENAME);
+            rendered_module_anchors.push(
+                box_html! {
+                    a(class="mod", href=href) {
+                        : prefix;
+                    }
+                    span: "::";
+                }
+                .into_string()?,
+            );
+            count -= 1;
+        }
+        Ok(rendered_module_anchors)
+    }
     /// Creates a String version of the path to an item,
     /// used in navigation between pages. The location given is the break point.
     ///

forc-plugins/forc-doc/src/main.rs

@@ -112,7 +112,7 @@ pub fn main() -> Result<()> {
         .project
         .forc_version
         .as_ref()
-        .map(|ver| format!("{}.{}.{}", ver.major, ver.minor, ver.patch));
+        .map(|ver| format!("Forc v{}.{}.{}", ver.major, ver.minor, ver.patch));
     let rendered_docs = RenderedDocumentation::from(
         raw_docs,
         RenderPlan::new(