Fix Markdown line lengths for Codacy compliance

- Break long lines in documentation files to stay under 120 characters
- Use reference-style links for long URLs
- Simplify ASCII art diagram in error-checking-feedback-loops.md
- Reorganize README.md badges with reference-style links

includes/Multisite/README.md

@@ -25,4 +25,5 @@ if ( is_multisite() ) {
 
 ## Testing
 
-For information on testing your plugin in a multisite environment, see the [Testing Framework](../../.wiki/Testing.md) documentation.
+For information on testing your plugin in a multisite environment, see the
+[Testing Framework](../../.wiki/Testing.md) documentation.