Documentation: clarify label matching (#55650)

* Documentation: clarify label matching

Behaviour in case of multiple matchers is not documented, but my experiments show they are reduced using logical AND. Please validate the updated description.

* Accept wording suggestion

Co-authored-by: brendamuir <100768211+brendamuir@users.noreply.github.com>

* Accept suggestion for docs/sources/alerting/fundamentals/annotation-label/labels-and-label-matchers.md

Co-authored-by: brendamuir <100768211+brendamuir@users.noreply.github.com>

* Improve wording according to review suggestions

Co-authored-by: brendamuir <100768211+brendamuir@users.noreply.github.com>

docs/sources/alerting/fundamentals/annotation-label/labels-and-label-matchers.md

@@ -30,15 +30,18 @@ A label matchers consists of 3 distinct parts, the **label**, the **value** and
 | `=~`     | Select labels that regex-match the value.          |
 | `!~`     | Select labels that do not regex-match the value.   |
 
-## Example of a label matcher
+If you are using multiple label matchers, they are combined using the AND logical operator. This means that all matchers must match in order to link a rule to a policy.
 
-Imagine we've defined the following set of labels for our alert.
+## Example scenario
+
+If you define the following set of labels for your alert:
 
 `{ foo=bar, baz=qux, id=12 }`
 
-In this situation,
+then:
 
-- A label matcher defined as `foo=bar` will match this alert rule.
-- A label matcher defined as `foo!=bar` will _not_ match this alert rule.
-- A label matcher defined as `id=~[0-9]+` will match this alert rule.
-- A label matcher defined as `baz!~[0-9]+` will match this alert rule.
+- A label matcher defined as `foo=bar` matches this alert rule.
+- A label matcher defined as `foo!=bar` does _not_ match this alert rule.
+- A label matcher defined as `id=~[0-9]+` matches this alert rule.
+- A label matcher defined as `baz!~[0-9]+` matches this alert rule.
+- Two label matchers defined as `foo=bar` and `id=~[0-9]+` match this alert rule.