docs: Merge intro into index (#1234)

The intro.md page and the index.md page were very similar in content.
Merge the two together, further polish the content,
and redirect the old intro.md page to index.md.

---------

Co-authored-by: Jacob Oaks <[email protected]>

docs/mkdocs.yml

@@ -87,6 +87,7 @@ plugins:
   # Redirect old links to new ones.
   - redirects:
       redirect_maps:
+        intro.md: index.md
         value-groups.md: value-groups/index.md
 
 
@@ -121,6 +122,15 @@ markdown_extensions:
         kwds:
           case: lower
 
+  # :foo-bar: emoji syntax.
+  #
+  # See https://squidfunk.github.io/mkdocs-material/reference/icons-emojis/
+  # to search through available emojis.
+  # The emojis are rendered into inline svgs at build time.
+  - pymdownx.emoji:
+      emoji_index: !!python/name:material.extensions.emoji.twemoji
+      emoji_generator: !!python/name:material.extensions.emoji.to_svg
+
   # GitHub-style task lists.
   - pymdownx.tasklist:
       custom_checkbox: true  # recommended
@@ -141,7 +151,6 @@ nav:
     - get-started/another-handler.md
     - get-started/many-handlers.md
     - get-started/conclusion.md
-  - intro.md
   - Concepts:
     - Container: container.md
     - Lifecycle: lifecycle.md

docs/src/index.md

@@ -6,19 +6,44 @@ Fx is **a dependency injection system for Go**.
 
 - **Eliminate globals**
 
-    Fx helps you remove global state from your application.
-    No more `init()` or global variables.
-    Use Fx-managed singletons.
+    ---
+
+    By using Fx-managed singletons,
+    you can eliminate global state from your application.
+    With Fx, you don't have to rely on `init()` functions for setup,
+    instead relying on Fx to manage the lifecycle of your application.
+
+- **Reduce boilerplate**
+
+    ---
+
+    Fx reduces the amount of code copy-pasted across your services.
+    It lets you define shared application setup in a single place,
+    and then reuse it across all your services.
+
+- **Automatic plumbing**
+
+    ---
+
+    Fx automatically constructs your application's dependency graph.
+    A component added to the application can be used by any other component
+    without any additional configuration.
+
+    [Learn more about the dependency container :material-arrow-right:](container.md)
 
 - **Code reuse**
 
+    ---
+
     Fx lets teams within your organization build loosely-coupled
-    and well-integrated shareable components.
+    and well-integrated shareable components referred to as modules.
+
+    [Learn more about modules :material-arrow-right:](modules.md)
 
 - **Battle-tested**
 
     Fx is the backbone of nearly all Go services at Uber.
 
 </div>
 
-[Get started](get-started/index.md){ .md-button .md-button--primary }
+[Get started :material-arrow-right-bold:](get-started/index.md){ .md-button .md-button--primary }