docs(github): improve comments for installation ID retrieval

Add detailed comments and improve readability in the
GetAndUpdateInstallationID and matchRepos functions.
Update comments to better explain the logic and purpose
of the code. Fix minor typos in comments.

pkg/provider/github/app/token.go

@@ -37,11 +37,16 @@ func NewInstallation(req *http.Request, run *params.Run, repo *v1alpha1.Reposito
 	}
 }
 
+// GetAndUpdateInstallationID retrieves and updates the installation ID for the GitHub App.
+// It generates a JWT token, lists all installations, and matches repositories to their installation IDs.
+// If a matching repository is found, it returns the enterprise host, token, and installation ID.
 func (ip *Install) GetAndUpdateInstallationID(ctx context.Context) (string, string, int64, error) {
 	var (
 		enterpriseHost, token string
 		installationID        int64
 	)
+
+	// Generate a JWT token for authentication
 	jwtToken, err := ip.GenerateJWT(ctx)
 	if err != nil {
 		return "", "", 0, err
@@ -50,14 +55,16 @@ func (ip *Install) GetAndUpdateInstallationID(ctx context.Context) (string, stri
 	apiURL := *ip.ghClient.APIURL
 	enterpriseHost = ip.request.Header.Get("X-GitHub-Enterprise-Host")
 	if enterpriseHost != "" {
-		// NOTE: Hopefully this works even when the ghe URL is on another host than the api URL
+		// NOTE: Hopefully this works even when the GHE URL is on another host than the API URL
 		apiURL = "https://" + enterpriseHost + "/api/v3"
 	}
 
 	logger := logging.FromContext(ctx)
 	opt := &gt.ListOptions{PerPage: ip.ghClient.PaginedNumber}
 	client, _, _ := github.MakeClient(ctx, apiURL, jwtToken)
 	installationData := []*gt.Installation{}
+
+	// List all installations
 	for {
 		installationSet, resp, err := client.Apps.ListInstallations(ctx, opt)
 		if err != nil {
@@ -70,9 +77,7 @@ func (ip *Install) GetAndUpdateInstallationID(ctx context.Context) (string, stri
 		opt.Page = resp.NextPage
 	}
 
-	/* each installationID can have list of repository
-	ref: https://docs.github.com/en/developers/apps/building-github-apps/authenticating-with-github-apps#authenticating-as-an-installation ,
-	     https://docs.github.com/en/rest/apps/installations?apiVersion=2022-11-28#list-repositories-accessible-to-the-app-installation */
+	// Iterate through each installation to find a matching repository
 	for i := range installationData {
 		if installationData[i].ID == nil {
 			return "", "", 0, fmt.Errorf("installation ID is nil")
@@ -102,27 +107,32 @@ func (ip *Install) GetAndUpdateInstallationID(ctx context.Context) (string, stri
 	return enterpriseHost, token, installationID, nil
 }
 
-// matchRepos matching github repositories to its installation IDs.
+// matchRepos matches GitHub repositories to their installation IDs.
+// It lists all repositories accessible to the app installation and checks if
+// any match the repository URL in the spec.
 func (ip *Install) matchRepos(ctx context.Context) (bool, error) {
 	installationRepoList, err := github.ListRepos(ctx, ip.ghClient)
 	if err != nil {
 		return false, err
 	}
 	ip.repoList = append(ip.repoList, installationRepoList...)
 	for i := range installationRepoList {
-		// If URL matches with repo spec url then we can break for loop
+		// If URL matches with repo spec URL then we can break the loop
 		if installationRepoList[i] == ip.repo.Spec.URL {
 			return true, nil
 		}
 	}
 	return false, nil
 }
 
+// JWTClaim represents the JWT claims for the GitHub App.
 type JWTClaim struct {
 	Issuer int64 `json:"iss"`
 	jwt.RegisteredClaims
 }
 
+// GenerateJWT generates a JWT token for the GitHub App.
+// It retrieves the application ID and private key, sets the claims, and signs the token.
 func (ip *Install) GenerateJWT(ctx context.Context) (string, error) {
 	// TODO: move this out of here
 	gh := github.New()