Update README.md

doc/ci/yaml/README.md

@@ -379,7 +379,7 @@ job:
     - bundle exec rspec
 ```
 
-Sometimes, `script` commands will need to be wrapped in single or double quotes. For example, commands that contain a colon (`:`) need to be wrapped in quotes so that the YAML parser knows to interpret the whole thing as a string rather than a "key: value" pair. Be careful when using special characters (`:`, `{`, `}`, `[`, `]`, `,`, `&`, `*`, `#`, `?`, `|`, `-`, `<`, `>`, `=`, `!`, `%`, `@`, `\``).
+Sometimes, `script` commands will need to be wrapped in single or double quotes. For example, commands that contain a colon (`:`) need to be wrapped in quotes so that the YAML parser knows to interpret the whole thing as a string rather than a "key: value" pair. Be careful when using special characters (`:`, `{`, `}`, `[`, `]`, `,`, `&`, `*`, `#`, `?`, `|`, `-`, `<`, `>`, `=`, `!`, `%`, `@`, `` ` ``).
 
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