[observability_pipelines] Clarify Grok source description (#3890)

Co-authored-by: ci.datadog-api-spec <packages@datadoghq.com>

Author: api-clients-generation-pipeline[bot]

.generator/schemas/v2/openapi.yaml

@@ -46179,7 +46179,7 @@ components:
             $ref: "#/components/schemas/ObservabilityPipelineParseGrokProcessorRuleMatchRule"
           type: array
         source:
-          description: The name of the field in the log event to apply the Grok rules to.
+          description: The value of the source field in log events to be processed by the Grok rules.
           example: "message"
           type: string
         support_rules:

services/observability_pipelines/src/v2/models/ObservabilityPipelineParseGrokProcessorRule.ts

@@ -14,7 +14,7 @@ export class ObservabilityPipelineParseGrokProcessorRule {
    */
   "matchRules": Array<ObservabilityPipelineParseGrokProcessorRuleMatchRule>;
   /**
-   * The name of the field in the log event to apply the Grok rules to.
+   * The value of the source field in log events to be processed by the Grok rules.
    */
   "source": string;
   /**