s/instantate/instantiate/ throughout. NFCI.

The static_assert in "libcxx/include/memory" was the main offender here,
but then I figured I might as well `git grep -i instantat` and fix all
the instances I found. One was in user-facing HTML documentation;
the rest were in comments or tests.

GitOrigin-RevId: e181a6aeddc26ef0512b2dba94db6360ba32f2ff
diff --git a/include/memory b/include/memory
index 9cdac6a..402a735 100644
--- a/include/memory
+++ b/include/memory
@@ -2028,7 +2028,7 @@
   // (The exception is std::function where it is possible that the function
   //  object and the allocator have the same type).
   static_assert((!is_same<_T1, _T2>::value),
-    "__compressed_pair cannot be instantated when T1 and T2 are the same type; "
+    "__compressed_pair cannot be instantiated when T1 and T2 are the same type; "
     "The current implementation is NOT ABI-compatible with the previous "
     "implementation for this configuration");