gui: label tx sizes as "vbytes" and feerates as "sat/vbyte"

closes https://github.com/spesmilo/electrum/issues/6961

electrum/util.py

@@ -792,10 +792,10 @@ def format_satoshis(
 
 FEERATE_PRECISION = 1  # num fractional decimal places for sat/byte fee rates
 _feerate_quanta = Decimal(10) ** (-FEERATE_PRECISION)
-UI_UNIT_NAME_FEERATE_SAT_PER_VBYTE = "sat/byte"
-UI_UNIT_NAME_FEERATE_SAT_PER_VB = "sat/b"
-UI_UNIT_NAME_TXSIZE_VBYTES = "bytes"
-UI_UNIT_NAME_MEMPOOL_MB = "MB"
+UI_UNIT_NAME_FEERATE_SAT_PER_VBYTE = "sat/vbyte"
+UI_UNIT_NAME_FEERATE_SAT_PER_VB = "sat/vB"
+UI_UNIT_NAME_TXSIZE_VBYTES = "vbytes"
+UI_UNIT_NAME_MEMPOOL_MB = "vMB"
 
 
 def format_fee_satoshis(fee, *, num_zeros=0, precision=None):