Document UpstreamRepoPath (#2566)

Fixes #2563

---------

Co-authored-by: Florian Stadler <[email protected]>

pkg/tfbridge/info/info.go

@@ -119,7 +119,18 @@ type Provider struct {
 	// Rules that control file discovery and edits for any subset of docs in a provider.
 	DocRules *DocRule
 
-	UpstreamRepoPath string // An optional path that overrides upstream location during docs lookup
+	// An optional file path to the root of the upstream provider's git repo, for use in docs generation.
+	//
+	// If UpstreamRepoPath is left blank, it is inferred to the location where Go downloaded the build
+	// dependency of the provider. The following fields influence the inference decision:
+	//
+	// - GitHubHost
+	// - GitHubOrg
+	// - Name
+	// - TFProviderModuleVersion
+	//
+	// This list may change over time.
+	UpstreamRepoPath string
 
 	// EXPERIMENTAL: the signature may change in minor releases.
 	//