Docs for upcoming v2.5.0 release (#216)

* docs: new `log` filters in Caddyfile

* docs: `renew_interval` global option

* docs: Update access log example

* docs: `log_credentials` global option

* docs: `vars`, `vars_regexp` matchers

* docs: `roll_uncompressed`, `roll_local_time`

* docs: `http_redirect` listener wrapper

* docs: `pki` app

* docs: `strict_sni_host` options

* docs: `default_bind` option

* docs: `method` directive

* docs: `tls internal` subdirectives

* Apply suggestions from code review

Co-authored-by: Matt Holt <mholt@users.noreply.github.com>

* Matchers, options, file_server, reverse_proxy

* More clarifications / corrections

* Corrections from review

* Typo fix

* One more note about dynamic upstreams

* Tab -> space

* Update module namespaces

* Update some docs about logging

* `copy_response`, `copy_response_headers`, `replace_status`

* `dns_challenge_domain_override`

* `caddy trust`, API endpoints

* `trusted_proxies`

* Note about `pass_thru` being only useful inside `route`

* Improve logging docs to clarify the difference

* A bit of polish on patterns

* request_body: Clarify error behavior

* review

Co-authored-by: Matt Holt <mholt@users.noreply.github.com>

src/docs/markdown/caddyfile/matchers.md

@@ -51,6 +51,8 @@ $(function() {
 	- [protocol](#protocol)
 	- [query](#query)
 	- [remote_ip](#remote-ip)
+	- [vars](#vars)
+	- [vars_regexp](#vars-regexp)
 
 
 ## Syntax
@@ -317,7 +319,7 @@ Match requests that do not have the `Foo` header field at all:
 header_regexp [<name>] <field> <regexp>
 ```
 
-Like `header`, but supports regular expressions. Capture groups can be accessed via [placeholder](/docs/caddyfile/concepts#placeholders) like `{re.name.capture_group}` where `name` is the name of the regular expression (optional, but recommended) and `capture_group` is either the name or number of the capture group in the expression. Capture group `0` is the full regexp match, `1` is the first capture group, `2` is the second capture group, and so on.
+Like [`header`](#header), but supports regular expressions. Capture groups can be accessed via [placeholder](/docs/caddyfile/concepts#placeholders) like `{re.name.capture_group}` where `name` is the name of the regular expression (optional, but recommended) and `capture_group` is either the name or number of the capture group in the expression. Capture group `0` is the full regexp match, `1` is the first capture group, `2` is the second capture group, and so on.
 
 The regular expression language used is RE2, included in Go. See the [RE2 syntax reference](https://github.com/google/re2/wiki/Syntax) and the [Go regexp syntax overview](https://pkg.go.dev/regexp/syntax).
 
@@ -457,7 +459,7 @@ Multiple `path` matchers will be OR'ed together.
 path_regexp [<name>] <regexp>
 ```
 
-Like `path`, but supports regular expressions. Capture groups can be accessed via [placeholder](/docs/caddyfile/concepts#placeholders) like `{re.name.capture_group}` where `name` is the name of the regular expression (optional, but recommended) and `capture_group` is either the name or number of the capture group in the expression. Capture group `0` is the full regexp match, `1` is the first capture group, `2` is the second capture group, and so on.
+Like [`path`](#path), but supports regular expressions. Capture groups can be accessed via [placeholder](/docs/caddyfile/concepts#placeholders) like `{re.name.capture_group}` where `name` is the name of the regular expression (optional, but recommended) and `capture_group` is either the name or number of the capture group in the expression. Capture group `0` is the full regexp match, `1` is the first capture group, `2` is the second capture group, and so on.
 
 The request path is URL-decoded, and cleaned (to collapse doubled-up slashes and directory traversal dots) before matching. For example `/foo*` will also match `//foo` and `/%2F/foo`.
 
@@ -516,7 +518,7 @@ query sort=asc
 remote_ip [forwarded] <ranges...>
 ```
 
-By remote (client) IP address. Accepts exact IPs or CIDR ranges. If the first argument is `forwarded`, then the first IP in the `X-Forwarded-For` request header, if present, will be preferred as the reference IP, rather than the immediate peer's IP, which is the default.
+By remote (client) IP address. Accepts exact IPs or CIDR ranges. If the first argument is `forwarded`, then the first IP in the `X-Forwarded-For` request header, if present, will be preferred as the reference IP, rather than the immediate peer's IP, which is the default. IPv6 zones are supported.
 
 Multiple `remote_ip` matchers will be OR'ed together.
 
@@ -527,3 +529,47 @@ Match requests from private IPv4 addresses.
 ```caddy-d
 remote_ip 192.168.0.0/16 172.16.0.0/12 10.0.0.0/8
 ```
+
+
+
+---
+### vars
+
+```caddy-d
+vars <variable> <values...>
+```
+
+By the value of a variable in the request context, or the value of a placeholder. Multiple values may be specified to match any of those possible values (OR'ed).
+
+This matcher is most useful when paired with the [`map` directive](/docs/caddyfile/directives/map) which sets outputs, or with plugins which set some information in the request context.
+
+#### Example:
+
+Match an output of the [`map` directive](/docs/caddyfile/directives/map) named `magic_number` for the values `3`, or `5`.
+
+```caddy-d
+vars {magic_number} 3 5
+```
+
+
+
+---
+### vars_regexp
+
+```caddy-d
+vars_regexp [<name>] <variable> <regexp>
+```
+
+Like [`vars`](#vars), but supports regular expressions. Capture groups can be accessed via [placeholder](/docs/caddyfile/concepts#placeholders) like `{re.name.capture_group}` where `name` is the name of the regular expression (optional, but recommended) and `capture_group` is either the name or number of the capture group in the expression. Capture group `0` is the full regexp match, `1` is the first capture group, `2` is the second capture group, and so on.
+
+The regular expression language used is RE2, included in Go. See the [RE2 syntax reference](https://github.com/google/re2/wiki/Syntax) and the [Go regexp syntax overview](https://pkg.go.dev/regexp/syntax).
+
+There can only be one `vars_regexp` matcher per named matcher.
+
+#### Example:
+
+Match an output of the [`map` directive](/docs/caddyfile/directives/map) named `magic_number` for a value starting with `4`, capturing the value in a capture group.
+
+```caddy-d
+vars_regexp magic {magic_number} ^(4.*)
+```