No markup rendering in --help

[knutwannheden]

The usage rendered by rg --help appears to contain some markup as rendered by the source code:

ripgrep/crates/core/app.rs

Lines 1354 to 1357 in fac4790

	When this flag is set, every file and directory is applied to it to test for
	a match. So for example, if you only want to search in a particular directory
	'foo', then *-g foo* is incorrect because 'foo/bar' does not match the glob
	'foo'. Instead, you should use *-g +++'foo/**'+++*.

In the rg --help output this looks the same:

            When this flag is set, every file and directory is applied to it to test for
            a match. So for example, if you only want to search in a particular directory
            'foo', then *-g foo* is incorrect because 'foo/bar' does not match the glob
            'foo'. Instead, you should use *-g +++'foo/**'+++*.

I suspect this is not as intended.