gitweb: prevent project search bar from overflowing on mobile

On narrow screens, the project search input can exceed the available width
and force page-wide horizontal scrolling.

Add side padding to the search container and cap the input to its container
width with border-box sizing, so the form stays within the viewport.

Signed-off-by: Rito Rhymes <rito@ritovision.com>

Author: ritorhymes

gitweb/static/gitweb.css

@@ -537,6 +537,13 @@ div.search {
 div.projsearch {
 	text-align: center;
 	margin: 20px 0px;
+	padding: 0 8px;
+	box-sizing: border-box;
+}
+
+div.projsearch input[type="text"] {
+	max-width: 100%;
+	box-sizing: border-box;
 }
 
 div.projsearch form {