Extended func support - doc update (#7161)

* Add support for extended promql functions in rule

Adds a flag to register the extended promql functions supported by the thanos
query engine when running the rule component.  This will allow rule config
files containing query expressions with (xrate / xincrease / xdelta) to pass
validation.  This will only work if the query endpoint in use is running the
thanos engine.

Signed-off-by: Samuel Dufel <samuel.dufel@shopify.com>

* Update rendered docs with added flag

Signed-off-by: Samuel Dufel <samuel.dufel@shopify.com>

---------

Signed-off-by: Samuel Dufel <samuel.dufel@shopify.com>

CHANGELOG.md

@@ -17,6 +17,7 @@ We use *breaking :warning:* to mark changes that are not backward compatible (re
 - [#7132](https://github.com/thanos-io/thanos/pull/7132) Documentation: fix broken helm installation instruction
 
 ### Added
+- [#7105](https://github.com/thanos-io/thanos/pull/7105) Rule: add flag `--query.enable-x-functions` to allow usage of extended promql functions (xrate, xincrease, xdelta) in loaded rules
 
 ### Changed
 
@@ -31,7 +32,6 @@ We use *breaking :warning:* to mark changes that are not backward compatible (re
 - [#7078](https://github.com/thanos-io/thanos/pull/7078) *: Bump gRPC to 1.57.2
 
 ### Added
-- [#7105](https://github.com/thanos-io/thanos/pull/7105) Rule: add flag `--query.enable-x-functions` to allow usage of extended promql functions (xrate, xincrease, xdelta) in loaded rules
 
 ### Changed
 

docs/components/rule.md

@@ -401,6 +401,10 @@ Flags:
       --query.default-step=1s    Default range query step to use. This is
                                  only used in stateless Ruler and alert state
                                  restoration.
+      --query.enable-x-functions
+                                 Whether to enable extended rate functions
+                                 (xrate, xincrease and xdelta). Only has effect
+                                 when used with Thanos engine.
       --query.http-method=POST   HTTP method to use when sending queries.
                                  Possible options: [GET, POST]
       --query.sd-dns-interval=30s