Doc for --tx-pool-hashes-max-size (#301)

* Doc for --ts-pool-hashes-max-size

Signed-off-by: grantnoble <grant.noble@consensys.net>

* Feedback from @shemnon (Danno Ferrin) about the value for --tx-pool-hashes-max-size

Signed-off-by: grantnoble <grant.noble@consensys.net>

docs/Concepts/Transactions/Transaction-Pool.md

@@ -12,6 +12,9 @@ Options and methods for configuring and monitoring the transaction pool include:
   method to list transactions in the transaction pool.
 * [`--tx-pool-max-size`](../../Reference/CLI/CLI-Syntax.md#tx-pool-max-size) command line option to
   specify the maximum number of transactions in the transaction pool.
+* [`--tx-pool-hashes-max-size`](../../Reference/CLI/CLI-Syntax.md#tx-pool-hashes-max-size) command
+  line option to specify the maximum number of transaction hashes in the transaction pool. Should
+  be greater than or equal to the value specified for `--tx-pool-max-size`.
 * [`--tx-pool-retention-hours`](../../Reference/CLI/CLI-Syntax.md#tx-pool-retention-hours) command
   line option to specify the maximum number of hours to keep pending transactions in the transaction
   pool.

docs/Reference/CLI/CLI-Syntax.md

@@ -2188,6 +2188,26 @@ tx-pool-max-size="2000"
 
 The maximum number of transactions kept in the transaction pool. The default is 4096.
 
+### tx-pool-hashes-max-size
+
+```bash tab="Syntax"
+--tx-pool-hashes-max-size=<INTEGER>
+```
+
+```bash tab="Command Line"
+--tx-pool-hashes-max-size=2000
+```
+
+```bash tab="Environment Variable"
+BESU_TX_POOL_HASHES_MAX_SIZE=2000
+```
+
+```bash tab="Configuration File"
+tx-pool-hashes-max-size="2000"
+```
+
+The maximum number of transaction hashes kept in the transaction pool. The default is 4096.
+
 ### tx-pool-retention-hours
 
 ```bash tab="Syntax"