SDL: Update and rename README.txt to README.md

From 3c78c211d57de4e9d953bf71d49d2ee313bbff34 Mon Sep 17 00:00:00 2001
From: "Ryan C. Gordon" <[EMAIL REDACTED]>
Date: Sat, 20 Mar 2021 18:46:37 -0400
Subject: [PATCH] Update and rename README.txt to README.md

This mostly just makes this look nice in web browsers with small displays,
like cell phones reading the GitHub project page.
---
 README.txt => README.md | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)
 rename README.txt => README.md (69%)

diff --git a/README.txt b/README.md
similarity index 69%
rename from README.txt
rename to README.md
index e8630c713..fa7f7ba0b 100644
--- a/README.txt
+++ b/README.md
@@ -1,11 +1,6 @@
 
-                         Simple DirectMedia Layer
+# Simple DirectMedia Layer (SDL) Version 2.0
 
-                                  (SDL)
-
-                                Version 2.0
-
----
 https://www.libsdl.org/
 
 Simple DirectMedia Layer is a cross-platform development library designed
@@ -18,4 +13,5 @@ More extensive documentation is available in the docs directory, starting
 with README.md
 
 Enjoy!
-	Sam Lantinga				(slouken@libsdl.org)
+
+Sam Lantinga (slouken@libsdl.org)