Introduce text faces

To easy text styling, a "Face" type is introduced which bundles a
collection of stylistic attributes together (essentially constituting a
typeface). This builds on the recently added Styled{String,Char} types,
and together allow for an ergonomic way of handling styled text.

base/client.jl

@@ -394,6 +394,19 @@ function load_InteractiveUtils(mod::Module=Main)
     return MainInclude.InteractiveUtils
 end
 
+"""
+    loadfaces!(facetoml::IO)
+
+Parse `facetoml` as TOML, and load all faces described.
+The loading is done with `loadfaces!`, which see.
+
+Face entries should be of the following form:
+```toml
+[face_name]
+property = "value"
+"""
+loadfaces!(facetoml::IO) = loadfaces!(TOML.parse(TOML.Parser(facetoml)))
+
 function load_REPL()
     # load interactive-only libraries
     try
@@ -416,6 +429,8 @@ function run_main_repl(interactive::Bool, quiet::Bool, banner::Symbol, history_f
         end
     end
     # TODO cleanup REPL_MODULE_REF
+    userfaces = joinpath(first(DEPOT_PATH), "config", "faces.toml")
+    isfile(userfaces) && open(loadfaces!, userfaces)
 
     if !fallback_repl && interactive && isassigned(REPL_MODULE_REF)
         invokelatest(REPL_MODULE_REF[]) do REPL

base/exports.jl

@@ -50,6 +50,7 @@ export
     Dims,
     Enum,
     ExponentialBackOff,
+    Face,
     IndexCartesian,
     IndexLinear,
     IndexStyle,
@@ -582,6 +583,7 @@ export
     ∪,
 
 # strings
+    addface!,
     ascii,
     bitstring,
     bytes2hex,
@@ -610,6 +612,7 @@ export
     isspace,
     isuppercase,
     isxdigit,
+    loadfaces!,
     lowercase,
     lowercasefirst,
     isvalid,