Fix missing await and syntax errors in documentation examples

[meliharik]

Follow-ups to the same classes of documentation bug fixed in #3940, #3936 and #3939 — I found remaining instances in other articles.

Missing await on TestStore (13 lines)

TestStore.send and TestStore.receive are both async, so these examples do not compile as written. TestingTCA.md was corrected in #3940; the same shape survives in three other articles, each inside a block that constructs a TestStore:

• Articles/Performance.md — 9 lines across the two "sharing logic" test examples
• Articles/Bindings.md — 2 lines in the binding-action test example
• Articles/FAQ.md — 2 lines, in the paragraph that explicitly introduces TestStore

Unbalanced parentheses (2 lines)

• Articles/MigrationGuides/MigratingTo1.10.md — @Shared(.fileStorage(URL(/* ... */) var signUpData is missing two closing parens. This is the same typo Fix SharingState documentation example syntax #3936 fixed in SharingState.md; that file now reads @Shared(.fileStorage(URL(/* ... */))) var users, and this line now matches it.
• Articles/MigrationGuides/MigratingTo1.11.md — the #Preview { … } example closes with ) instead of }.

How I found them

I extracted all 362 ```swift blocks from the DocC sources and checked paren/bracket balance outside strings and comments, then cross-checked every store.send/`store.receive` against whether its block builds a `TestStore`. Braces were deliberately not balance-checked, since the docs legitimately show fragments.

Two things I deliberately left alone:

• Articles/StackBasedNavigation.md:212 also calls store.send(.detailButtonTapped) without await, but that one is inside a SwiftUI Button and so is the synchronous Store.send — correct as written.
• Articles/MigrationGuides/MigratingTo1.15.md:38 has an unbalanced ]) , but it reads as an intentional excerpt from the middle of a .target(…) call rather than a typo. Happy to adjust if you'd prefer it balanced.

I did not touch the store.receive calls in the 1.4 and 1.9 migration guides, since those are illustrating an older API era and it wasn't obvious whether you want them modernized.