[docs] note about doubled transit tunnels limit for floodfill mode

Signed-off-by: R4SAS <r4sas@i2pmail.org>

ChangeLog

@@ -15,6 +15,7 @@
 - Removed SSU support
 - Reduced bandwidth calculation interval from 60 to 15 seconds
 - Increased default max transit tunnels number from 2500 to 5000 or 10000 for floodfill
+- Transit tunnels limit is doubled if floodfill mode is enabled
 - NTCP2 and SSU2 timestamps are rounded to seconds
 - Drop RouterInfos and LeaseSets with timestamp from future
 - Don't delete unreachable routers if tunnel creation success rate is too low

contrib/i2pd.conf

@@ -238,6 +238,7 @@ verify = true
 
 [limits]
 ## Maximum active transit sessions (default: 5000)
+## This value is doubled if floodfill mode is enabled!
 # transittunnels = 5000
 ## Limit number of open file descriptors (0 - use system limit)
 # openfiles = 0