join and homogenize HTML & CSS section title across files (#6963)

more/free-programming-cheatsheets.md

@@ -11,7 +11,7 @@
 * [Docker](#docker)
 * [Git](#git)
 * [Go](#go)
-* [HTML / CSS](#html--css)
+* [HTML and CSS](#html-and-css)
 * [IDE / Editors](#ide--editors)
 * [Java](#java)
 * [JavaScript](#javascript)
@@ -125,7 +125,7 @@
 * [Go Cheatsheet](https://devhints.io/go) - devhints, Rico Santa Cruz (HTML)
 
 
-### HTML / CSS
+### HTML and CSS
 
 * [CSS CheatSheet](https://htmlcheatsheet.com/css/) (HTML)
 * [CSS Flexbox Cheatsheet](https://css-tricks.com/snippets/css/a-guide-to-flexbox/) - Chris Coyier (HTML)

more/free-programming-interactive-tutorials-en.md

@@ -16,7 +16,7 @@
 * [GLSL](#glsl)
 * [Go](#go)
 * [Haskell](#haskell)
-* [HTML / CSS](#html--css)
+* [HTML and CSS](#html-and-css)
   * [Bootstrap](#bootstrap)
 * [Java](#java)
 * [JavaScript](#javascript)
@@ -156,7 +156,7 @@
 * [Try Haskell!](http://tryhaskell.org)
 
 
-### HTML / CSS
+### HTML and CSS
 
 * [CSS Diner](http://flukeout.github.io)
 * [CSS Speedrun \| Test your CSS Skills](https://css-speedrun.netlify.app) - Vincent Will (HTML)

more/free-programming-interactive-tutorials-ja.md

@@ -1,12 +1,12 @@
 ### Index
 
-* [HTML / CSS](#html--css)
+* [HTML and CSS](#html-and-css)
 * [JavaScript](#javascript)
   * [React](#react)
 * [Python](#python)
 
 
-### HTML / CSS
+### HTML and CSS
 
 * [レスポンシブウェブデザイン](https://www.freecodecamp.org/japanese/learn/responsive-web-design) - freeCodeCamp
 

more/free-programming-playgrounds.md

@@ -7,7 +7,6 @@
 * [C++](#cpp)
 * [ClojureScript](#clojurescript)
 * [Crystal](#crystal)
-* [CSS](#css)
 * [Dart](#dart)
 * [Docker](#docker)
 * [Elm](#elm)
@@ -16,6 +15,7 @@
 * [Git](#git)
 * [Go](#go)
 * [Haskell](#haskell)
+* [HTML and CSS](#html-and-css)
 * [Ionic](#ionic)
 * [Java](#java)
 * [JavaScript](#javascript)
@@ -93,15 +93,6 @@
 * [Compile & run code in Crystal](https://play.crystal-lang.org/#/cr)
 
 
-### CSS
-
-* [CodePen](https://codepen.io)
-* [CSSdeck](https://cssdeck.com)
-* [Dabblet](https://dabblet.com)
-* [Flexy Boxes](https://the-echoplex.net/flexyboxes/)
-* [SoloLearn](https://code.sololearn.com/web#css)
-
-
 ### Dart
 
 * [DartPad](https://dartpad.dev)
@@ -146,6 +137,15 @@
 * [Try Haskell](https://www.tryhaskell.org)
 
 
+### HTML and CSS
+
+* [CodePen](https://codepen.io)
+* [CSSdeck](https://cssdeck.com)
+* [Dabblet](https://dabblet.com)
+* [Flexy Boxes](https://the-echoplex.net/flexyboxes/)
+* [SoloLearn](https://code.sololearn.com/web#css)
+
+
 ### Ionic
 
 * [StackBlitz](https://stackblitz.com/fork/ionic)