Added copy button to crate version

Author: MeetThePatel

src/librustdoc/html/static/css/rustdoc.css

@@ -618,6 +618,29 @@ ul.block, .block li, .block ul {
 	padding-left: var(--sidebar-elems-left-padding);
 }
 
+#copy-cargo-snippet {
+	color: var(--main-color);
+	background: var(--sidebar-background-color);
+	margin-left: 10px;
+	padding: 0;
+	padding-left: 2px;
+	border: 0;
+	font-size: 0;
+
+    scale: 80%;
+    justify-content: center;
+}
+#copy-cargo-snippet::before {
+	filter: var(--copy-path-img-filter);
+	content: var(--clipboard-image);
+}
+#copy-cargo-snippet:hover::before {
+	filter: var(--copy-path-img-hover-filter);
+}
+#copy-cargo-snippet.clicked::before {
+	content: var(--checkmark-image);
+}
+
 .sidebar a {
 	color: var(--sidebar-link-color);
 }
@@ -740,6 +763,9 @@ ul.block, .block li, .block ul {
 	font-weight: normal;
 	font-size: 1rem;
 	overflow-wrap: break-word;
+
+    display: flex;
+    align-items: center;
 }
 
 .sidebar-crate + .version {

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

@@ -1823,6 +1823,19 @@ href="https://doc.rust-lang.org/${channel}/rustdoc/read-documentation/search.htm
         copyButtonAnimation(but);
     };
 
+    // Copy button that appears next to the crate version.
+    const crate_version_copy_button = document.getElementById("copy-cargo-snippet");
+    if (!crate_version_copy_button) {
+        return;
+    }
+    crate_version_copy_button.onclick = () => {
+        let crate_version = crate_version_copy_button.parentElement.textContent;
+        let snippet = `${window.currentCrate} = "${crate_version}"`;
+
+        copyContentToClipboard(snippet);
+        copyButtonAnimation(crate_version_copy_button);
+    };
+
     // Copy buttons on code examples.
     function copyCode(codeElem) {
         if (!codeElem) {

src/librustdoc/html/templates/page.html

@@ -100,7 +100,7 @@
             <h2> {# #}
                 <a href="{{page.root_path|safe}}{{display_krate_with_trailing_slash|safe}}index.html">{{display_krate|wrapped|safe}}</a> {# #}
                 {% if !display_krate_version_number.is_empty() %}
-                    <span class="version">{{+ display_krate_version_number}}</span>
+                    <span class="version">{{+ display_krate_version_number}}<button id="copy-cargo-snippet" title="Copy Cargo.toml snippet to clipboard">{# #}</button></span>
                 {% endif %}
             </h2> {# #}
         </div> {# #}