Readme rule examples are inverted

[edmorley]

I just tried to use coverage-conditional-plugin by following the README, however pytest-cov was still reporting less than 100% coverage.

After going down a rabbit hole of thinking that my pyproject.toml settings weren't being picked up (eg the plugin not being activated, or similar), I discovered that the cause was that my pragma rules were inverted.

I'd used:

if sys.version_info < (3, 11):
    import tomli as tomllib  # pragma: py-lt-311
else:
    import tomllib  # pragma: py-gte-311

Instead of:

if sys.version_info < (3, 11):
    import tomli as tomllib  # pragma: py-gte-311
else:
    import tomllib  # pragma: py-lt-311

I only discovered this by chance, after seeing:
#179 (comment)

I'd followed the docs, however they appear to have the example inverted too:

coverage-conditional-plugin/README.md

Lines 64 to 87 in 22c1093

	## Example
	Imagine that we have this code:
	```python
	try: # pragma: has-django
	import django
	except ImportError: # pragma: has-no-django
	django = None
	def run_if_django_is_installed():
	if django is not None: # pragma: has-django
	...
	```
	And here's the configuration you might use:
	```ini
	[coverage:coverage_conditional_plugin]
	rules =
	"is_installed('django')": has-django
	"not is_installed('django')": has-no-django
	```

In addition to fixing this example, maybe it's worth adding the `pragma: some` means `pragma: no cover if some` explanation to the README too? (Given I'm not the first person to be confused about this, given #179 etc) :-)