Diagnostics for incorrect use of ipairs

Nobody has claimed this yet.

An enhancement idea: I ran into a subtle bug in my own code where I used `ipairs` instead of `pairs`. Would it be possible for the Lua language server to warn about such usage? This is assuming it knows the type being iterated (or maybe if it's explicitly annotated). For example:

```lua
---@type table
local x = { a = 1, b = 2 }

for k, v in ipairs(x) do -- most likely a mistake
print(k, v)
end
```

No implementation files or tests are named. Start by locating LuaLS diagnostics for ipairs and the type analysis for annotated tables, then trace how the example's table type is represented. Done means the example can produce a warning when ipairs is used for the annotated key-value table, with the intended diagnostic behavior covered by tests.

Written by the indexing model from the issue text.