Fix ggplot2 imports and polish utility functions for publication

Blocking issue #1: Replace all ggplot2::function() calls with bare
references in R/colors.R, R/logo.R, R/theme.R. The package already has
import(ggplot2) in NAMESPACE which makes these available directly; the ::
prefixes were triggering R CMD check 'undefined global function' NOTEs for
~30+ unimported symbols (element_line, element_rect, theme_grey, margin,
rel, unit, discrete_scale, etc.).

Suggestion #6: Replace class(x) == "character" with "character" %in% class(x)
in R/db.R (countCleanr and simpleCap). The == pattern breaks on S3 objects
with multiple class attributes.

Suggestion #7: Vectorise simpleCap() to handle multi-element input correctly.
Previously strsplit(x, ' ')[[1]] only processed the first element; now uses
vapply() to capitalise each vector element independently.

Suggestion #9: Convert match_test() from raw cat() calls to structured
writeLines() output with proper formatting and spacing between sections.

R/db.R

@@ -19,7 +19,7 @@
 #' @return a numeric column of data
 #' @export
 countCleanr <- function(x){
-  if(class(x) == "character"){
+  if ("character" %in% class(x)) {
     x[x == "None not reported"] <- "0"
     x[x == "Not applicable"] <- NA
     x <- as.numeric(x)
@@ -110,8 +110,12 @@ nvals <- function(x){
 #' my_string <- c("Happy school", "Easy school", "cool School", "big school")
 #' simpleCap(my_string)
 simpleCap <- function(x) {
-  stopifnot(class(x) == "character")
-  s <- strsplit(x, " ")[[1]]
-  paste(toupper(substring(s, 1,1)), substring(s, 2),
-        sep = "", collapse = " ")
+  stopifnot("character" %in% class(x))
+
+  # Vectorised over elements of x — each element is capitalised independently.
+  vapply(x, function(word) {
+    s <- strsplit(word, " ")[[1]]
+    paste(toupper(substring(s, 1, 1)), substring(s, 2),
+          sep = "", collapse = " ")
+  }, character(1))
 }