docs: Add path_regexp option for uri directive (#144)

ad8d01cb66

src/docs/markdown/caddyfile/directives/uri.md

@@ -12,7 +12,7 @@ This directive is distinct from [`rewrite`](rewrite) in that `uri` _partially_ c
 ## Syntax
 
 ```caddy-d
-uri [<matcher>] strip_prefix|strip_suffix|replace \
+uri [<matcher>] strip_prefix|strip_suffix|replace|path_regexp \
 	<target> \
 	[<replacement> [<limit>]]
 ```
@@ -21,8 +21,9 @@ uri [<matcher>] strip_prefix|strip_suffix|replace \
 	- **strip_prefix** strips a prefix from the path, if it has the prefix.
 	- **strip_suffix** strips a suffix from the path, if it has the suffix.
 	- **replace** performs a substring replacement across the whole URI.
+	- **path_regexp** performs a regular expression replacement on the path portion of the URI.
 - **&lt;target&gt;** is the prefix, suffix, or search string/regular expression. If a prefix, the leading forward slash may be omitted, since paths always start with a forward slash.
-- **&lt;replacement&gt;** is the replacement string (only valid with `replace`).
+- **&lt;replacement&gt;** is the replacement string (only valid with `replace` and `path_regexp`).
 - **&lt;limit&gt;** is an optional limit to the maximum number of replacements (only valid with `replace`).
 
 
@@ -45,3 +46,9 @@ Replace "/docs/" with "/v1/docs/" in any request URI:
 ```caddy-d
 uri replace /docs/ /v1/docs/
 ```
+
+Collapse all repeated slashes in the request path (but not the request query) to a single slash:
+
+```caddy-d
+uri path_regexp /{2,} /
+```