chore: auto-update metadata coverage in METADATA_SUPPORT.md [no ci]

Author: svc-cli-bot

METADATA_SUPPORT.md

@@ -4,7 +4,7 @@ This list compares metadata types found in Salesforce v64 with the [metadata reg
 
 This repository is used by both the Salesforce CLIs and Salesforce's VSCode Extensions.
 
-Currently, there are 656/689 supported metadata types.
+Currently, there are 657/689 supported metadata types.
 For status on any existing gaps, please search or file an issue in the [Salesforce CLI issues only repo](https://github.com/forcedotcom/cli/issues).
 To contribute a new metadata type, please see the [Contributing Metadata Types to the Registry](./contributing/metadata.md)
 
@@ -313,7 +313,7 @@ To contribute a new metadata type, please see the [Contributing Metadata Types t
 |FeatureParameterBoolean|✅||
 |FeatureParameterDate|✅||
 |FeatureParameterInteger|✅||
-|FieldMappingConfig|❌|Not supported, but support could be added|
+|FieldMappingConfig|✅||
 |FieldRestrictionRule|✅||
 |FieldServiceMobileConfig|✅||
 |FieldServiceMobileExtension|✅||
@@ -764,6 +764,7 @@ v65 introduces the following new types.  Here's their current level of support
 - extDataTranFieldTemplate
 - ExtlClntAppSampleConfigurablePolicies
 - ExtlClntAppSampleSettings
+- FieldMappingConfigItem
 - Form
 - FormSection
 - GenAiPlanner