[R-package] Improves logging in lint_r_code.R (fixes #3471) (#3472)

* Update lint_r_code.R

* improves logging in lint_r_code

* Update .ci/lint_r_code.R
Co-authored-by: James Lamb <jaylamb20@gmail.com>
Co-authored-by: James Lamb <jaylamb20@gmail.com>

.ci/lint_r_code.R

@@ -86,7 +86,7 @@ LINTERS_TO_USE <- list(
     , "unneeded_concatenation" = lintr::unneeded_concatenation_linter
 )
 
-print(sprintf("Found %i R files to lint\n", length(FILES_TO_LINT)))
+noquote(paste0(length(FILES_TO_LINT), " R files need linting"))
 
 results <- NULL
 
@@ -113,6 +113,8 @@ for (r_file in FILES_TO_LINT) {
 
 issues_found <- length(results)
 
+noquote(paste0("Total linting issues found: ", issues_found))
+
 if (issues_found > 0L) {
     print(results)
 }