docs: add docs for snapshot agent local_scratch_path option (#7730)

Also fix some website upgrade bugs.

website/pages/docs/commands/snapshot/agent.mdx

@@ -82,7 +82,7 @@ Usage: `consul snapshot agent [options]`
   Config files referenced using `-config-dir` and `-config-file` have the following
   format (shown populated with default values):
 
-```javascript
+```json
   {
     "snapshot_agent": {
       "http_addr": "127.0.0.1:8500",
@@ -105,7 +105,8 @@ Usage: `consul snapshot agent [options]`
         "service": "consul-snapshot",
         "deregister_after": "72h",
         "lock_key": "consul-snapshot/lock",
-        "max_failures": 3
+        "max_failures": 3,
+        "local_scratch_path": ""
       },
       "local_storage": {
         "path": "."
@@ -116,9 +117,9 @@ Usage: `consul snapshot agent [options]`
         "s3_region": "",
         "s3_bucket": "",
         "s3_key_prefix": "consul-snapshot",
-        "s3_server_side_encryption":false,
-        "s3_static_snapshot_name":""
-      }
+        "s3_server_side_encryption": false,
+        "s3_static_snapshot_name": ""
+      },
       "azure_blob_storage": {
         "account_name": "",
         "account_key": "",
@@ -139,7 +140,7 @@ if desired.
 
 #### Snapshot Options
 
-- <a name="interval">`-interval`</a> - Interval at which to perform snapshots as
+- `-interval` - Interval at which to perform snapshots as
   a time with a unit suffix, which can be "s", "m", "h" for seconds, minutes, or
   hours. If 0 is provided, the agent will take a single snapshot and then exit, which
   is useful for running snapshots via batch jobs. Defaults to "1h"
@@ -161,6 +162,11 @@ if desired.
   snapshots. If this is set to 0, the agent will not perform this and snapshots
   will accumulate forever. Defaults to 30.
 
+- `-local-scratch-path` - Location to store all temporary snapshots in prior to
+  sending them off to the configured storage backend. If not configured the
+  system temporary directory will be used. When using the local storage backend
+  this is not configurable and `-local-path` will be used.
+
 #### Agent Options
 
 - `-deregister-after` - An interval, after which if the agent is unhealthy it will be