Needs a "don't use truthy types in a conditional/boolean context" diagnostic

Nobody has claimed this yet.

### How are you using the lua-language-server?

Visual Studio Code Extension (sumneko.lua)

### Which OS are you using?

Windows

### What is the issue affecting?

Type Checking, Diagnostics/Syntax Checking

### Expected Behaviour

When variable `a` has a truthy type (e.g. any type that does not contain `boolean` or `nil`), then the following lines should all give warnings, since (assuming the type annotations are correct and `Weak Nil Check` is off) `a` cannot be `nil` or `false`, and thus can never resolve to `false` in a boolean context, and so the operations are pointless:
```lua
if a then print("1") end -- will always print 1
if not a then print("2") end -- will never print 2
local b = a or "3" -- equivalent to b = a
local c = a and "4" or "5" -- equivalent to c = "4"
```

### Actual Behaviour

None of those lines warn you about anything under the current diagnostics

### Reproduction steps

1. Type the following into a lua file:
```lua
---@param a number (or string, table, etc.)
function A(a)
if a then print("1") end
if not a then print("2") end
local b = a or "3"
local c = a and "4" or "5"
end
```
2. Observe the lack of diagnostic warnings on each line inside the function

(I would also like a "no-unparameterized-tables" diagnostic where plain `table` without any <> does not count as a valid type)

Start by reproducing the supplied Lua snippet in a Lua file through the Visual Studio Code extension, then trace the type-checking and diagnostic entry points that handle conditionals and boolean expressions. Done means the requested cases produce appropriate warnings; the separate no-unparameterized-tables request also needs its scope decided.

Written by the indexing model from the issue text.