fix(search): drop stray braces that break search results box styles

[lunny]

What/Why/How?

SearchResultsBox in src/components/SearchBox/styled.elements.tsx has an extra } after three interpolations (background-color, border-top, border-bottom):

background-color: ${({ theme }) => darken(0.05, theme.sidebar.backgroundColor)}};

With styled-components v6 (stylis 4) the first stray brace closes the rule early, so everything after background-color is emitted outside the class rule and dropped by the browser:

// broken (current main)
.GvrvM{padding:5px 0;background-color:#f2f2f2;}
color:#333;
min-height:150px;
max-height:250px;
margin-top:10px;
line-height:1.4;
font-size:0.9em;

// after this PR
.kuYQEX{padding:5px 0;background-color:#f2f2f2;color:#333;min-height:150px;max-height:250px;margin-top:10px;line-height:1.4;font-size:0.9em;}

styled-components v5 (stylis 3.5) happens to tolerate the stray brace, which is why this is invisible in the bundled demo but breaks consumers that supply styled-components v6 — and v6 is an allowed peer range (^4.1.1 || ^5.1.1 || ^6.0.5).

The user-visible symptom is that the search results are not scrollable and no scrollbar appears. Because max-height: 250px is lost, the results box grows to the full result list height (measured 5838px for a 79-result query), so its perfect-scrollbar container has clientHeight === scrollHeight, PS keeps .ps__rail-y at display: none, and the sidebar (overflow: hidden) clips everything below the viewport. Results exist but are unreachable. color, margin-top, line-height, font-size, li { background-color: inherit } and the compact MenuItemLabel padding are lost too, so result rows also render oversized.

Fix: remove the three stray }. The change is whitespace-only in effect on the source, but restores all of the intended declarations.

Note: border-top/border-bottom only specify a colour, so with border-style defaulting to none they still paint nothing — same as today's behaviour. I kept the diff minimal instead of guessing 1px solid; happy to add it if that was the original intent (it was border-top: 1px solid #e1e1e1 before 1bf490c).

Reference

Introduced in 1bf490c (fix: search-box use theme, first released in v2.0.0-rc.19); a0bd27c later renamed theme.menu.* to theme.sidebar.* and kept the typo.

Reported downstream (redocusaurus / Docusaurus 3, which uses styled-components 6): https://gitea.com/gitea/docs/issues/257

Tests

• Reproduced the stylis-4 truncation with a minimal styled-components 6.1.17 + ServerStyleSheet snippet (output above); the same snippet on styled-components 5 shows the brace being tolerated.
• Verified against a real redoc-rendered site (docs.gitea.com API reference, redoc 2.4.0 via redocusaurus): before, results box = 5838px, container scrollHeight === clientHeight, no ps--active-y, .ps__rail-y display: none, scrolling impossible. After applying the missing declarations: box = 250px, scrollHeight 3674px, ps--active-y set, rail visible, scrolling works.
• e2e/integration/search.e2e.ts keeps passing on selectors ([data-role="search:results"]), unchanged.

Check yourself

• Code is linted
• Tested
• All new/updated code is covered with tests