Fix x-refs in docs for the new metric name changes

Signed-off-by: Sahas Subramanian <[email protected]>

Author: shsms

src/frequenz/sdk/timeseries/ev_charger_pool/_ev_charger_pool.py

@@ -33,8 +33,8 @@ class EVChargerPool:
 
     Provides:
       - Aggregate [`power`][frequenz.sdk.timeseries.ev_charger_pool.EVChargerPool.power]
-        and 3-phase
-        [`current`][frequenz.sdk.timeseries.ev_charger_pool.EVChargerPool.current]
+        and
+        [`current_per_phase`][frequenz.sdk.timeseries.ev_charger_pool.EVChargerPool.current_per_phase]
         measurements of the EV Chargers in the pool.
     """
 

src/frequenz/sdk/timeseries/formula_engine/_formula_engine.py

@@ -443,9 +443,9 @@ class FormulaEngine3Phase(
     [`FormulaEngine`][frequenz.sdk.timeseries.formula_engine.FormulaEngine], except that
     they stream [3-phase samples][frequenz.sdk.timeseries.Sample3Phase].  All the
     current formulas (like
-    [`Grid.current`][frequenz.sdk.timeseries.grid.Grid.current],
-    [`EVChargerPool.current`][frequenz.sdk.timeseries.ev_charger_pool.EVChargerPool.current],
-    etc.) are implemented as 3-phase formulas.
+    [`Grid.current_per_phase`][frequenz.sdk.timeseries.grid.Grid.current_per_phase],
+    [`EVChargerPool.current_per_phase`][frequenz.sdk.timeseries.ev_charger_pool.EVChargerPool.current_per_phase],
+    etc.) are implemented as per-phase formulas.
 
     ### Streaming Interface