Fix Citation modal responsiveness and clipboard copy (#29799)

The modal was broken in two ways:

- On small screens, the input box was partially hanging outside the
modal. Fixed with flexbox and increased modal width.
- The clipboard copy was not working because the modal had both
`data-clipboard-text` and `data-clipboard-target`, while we only support
one of those. Made a small tweak in clipboard as well so that it will
still fall back to target if text is empty.

(cherry picked from commit 94512ee0628dc0d2b697441a4355ace54b6515cd)

templates/repo/cite/cite_buttons.tmpl

@@ -6,6 +6,6 @@ BibTeX
 </button>
 <!-- the value will be updated by initCitationFileCopyContent, the code below is used to avoid UI flicking  -->
 <input id="citation-copy-content" value="" size="1" readonly>
-<button class="ui icon button" id="citation-clipboard-btn" data-tooltip-content="{{ctx.Locale.Tr "copy"}}" data-clipboard-text="" data-clipboard-target="#citation-copy-content">
+<button class="ui icon button" id="citation-clipboard-btn" data-tooltip-content="{{ctx.Locale.Tr "copy"}}" data-clipboard-target="#citation-copy-content">
 	{{svg "octicon-copy"}}
 </button>

templates/repo/cite/cite_modal.tmpl

@@ -1,10 +1,9 @@
-<div class="ui tiny modal" id="cite-repo-modal">
+<div class="ui small modal" id="cite-repo-modal">
 	<div class="header">
 		{{ctx.Locale.Tr "repo.cite_this_repo"}}
 	</div>
 	<div class="content">
 		<div class="ui stackable secondary menu">
-			<div class="fitted item">
 			<div class="ui action input" id="citation-panel">
 				{{template "repo/cite/cite_buttons" .}}
 				<a id="goto-citation-btn" class="ui basic jump icon button" href="{{$.RepoLink}}/src/{{$.BranchName}}/CITATION.cff" data-tooltip-content="{{ctx.Locale.Tr "repo.find_file.go_to_file"}}">
@@ -13,7 +12,6 @@
 			</div>
 		</div>
 	</div>
-	</div>
 	<div class="actions">
 		<button class="ui cancel button">
 			{{ctx.Locale.Tr "cancel"}}

web_src/css/repo.css

@@ -2034,13 +2034,8 @@
 }
 
 #cite-repo-modal #citation-panel {
-  width: 500px;
-}
-
-@media (max-width: 767.98px) {
-  #cite-repo-modal #citation-panel {
+  display: flex;
   width: 100%;
-  }
 }
 
 #cite-repo-modal #citation-panel input {
@@ -2060,6 +2055,7 @@
   padding: 5px 10px;
   font-size: 1.2em;
   line-height: 1.4;
+  flex: 1;
 }
 
 #cite-repo-modal #citation-panel #citation-copy-apa,

web_src/js/features/clipboard.js

@@ -15,10 +15,8 @@ export function initGlobalCopyToClipboardListener() {
 
     e.preventDefault();
 
-    let text;
-    if (target.hasAttribute('data-clipboard-text')) {
-      text = target.getAttribute('data-clipboard-text');
-    } else {
+    let text = target.getAttribute('data-clipboard-text');
+    if (!text) {
       text = document.querySelector(target.getAttribute('data-clipboard-target'))?.value;
     }