rustdoc: search for slices and arrays by type with []

src/doc/rustdoc/src/how-to-read-rustdoc.md

@@ -105,6 +105,11 @@ will match these queries:
 
 But it *does not* match `Result<Vec, u8>` or `Result<u8<Vec>>`.
 
+Function signature searches also support arrays and slices. The explicit name
+`primitive:slice<u8>` and `primitive:array<u8>` can be used to match a slice
+or array of bytes, while square brackets `[u8]` will match either one. Empty
+square brackets, `[]`, will match any slice regardless of what it contains.
+
 ### Shortcuts
 
 Pressing `S` while focused elsewhere on the page will move focus to the

src/librustdoc/html/static/js/main.js

@@ -1077,6 +1077,10 @@ function preLoadCss(cssUrl) {
              <code>-&gt; vec</code> or <code>String, enum:Cow -&gt; bool</code>)",
             "You can look for items with an exact name by putting double quotes around \
              your request: <code>\"string\"</code>",
+             "Look for functions that accept or return \
+              <a href=\"https://doc.rust-lang.org/std/primitive.slice.html\">slices</a> and \
+              <a href=\"https://doc.rust-lang.org/std/primitive.array.html\">arrays</a> by writing \
+              square brackets (e.g., <code>-&gt; [u8]</code> or <code>[] -&gt; Option</code>)",
             "Look for items inside another one by searching for a path: <code>vec::Vec</code>",
         ].map(x => "<p>" + x + "</p>").join("");
         const div_infos = document.createElement("div");