Fix NeoPool SENSOR JSON key: "Module" → "Modules"

[alexdelprete]

The NeoPool SENSOR telemetry JSON uses "Modules" (plural) as the key name, but the documentation shows "Module" (singular) in the example payload and descriptive text.

The Tasmota source code confirms "Modules" is correct:

• xsns_83_neopool.ino defines D_NEOPOOL_JSON_MODULES = "Modules"
• The NPControl example in this same doc already correctly uses "Modules"

This was discussed with @curzon01, who requested the fix here.

Changes (3 lines in docs/NeoPool.md)

Line 137 — SENSOR JSON example:

-    "Module": {
+    "Modules": {

Line 315 — Description text:

- ...the corresponding "Module" subkey must be `1`)
+ ...the corresponding "Modules" subkey must be `1`)

Line 319 — Reference to SENSOR topic:

- To check which modules are installed use the `Module` value from SENSOR topic
+ To check which modules are installed use the `Modules` value from SENSOR topic