README.md: Add 'Garbled output' to 'Troubleshooting' (#1937)

As per #234, #403, #1572, #1823 and #1897, this commit clarifies that
`bat` cannot properly handle escape sequences.

Signed-off-by: Isabella Basso <isabbasso@riseup.net>

README.md

@@ -674,6 +674,13 @@ bat() {
 
 ## Troubleshooting
 
+### Garbled output
+
+If an input file contains color codes or other ANSI escape sequences, `bat` will have problems
+performing syntax highlighting and text wrapping, and thus the output can become garbled.
+When displaying such files it is recommended to disable both syntax highlighting and wrapping by
+passing the `--color=never --wrap=never` options to `bat`.
+
 ### Terminals & colors
 
 `bat` handles terminals *with* and *without* truecolor support. However, the colors in most syntax