fix: correct RelativeStrengthAB binding wrapper casing (#296)

The WASM and Node binding wrappers were named with the lowercase-b acronym
(WasmRelativeStrengthAb, RelativeStrengthAbNode) while the core type and every
other surface use RelativeStrengthAB. The published JS/WASM class name was
already correct via js_name/js_class, so this only aligns the internal Rust
identifiers and the auto-generated TypeScript type alias
(RelativeStrengthAbNode -> RelativeStrengthABNode). Runtime API unchanged.

bindings/node/index.d.ts

@@ -1645,7 +1645,7 @@ export declare class Cointegration {
   isReady(): boolean
   warmupPeriod(): number
 }
-export type RelativeStrengthAbNode = RelativeStrengthAB
+export type RelativeStrengthABNode = RelativeStrengthAB
 export declare class RelativeStrengthAB {
   constructor(maPeriod: number, rsiPeriod: number)
   update(a: number, b: number): RelativeStrengthValue | null