Change font::print_wrap text argument from std::string to const char*

We no longer need to pass a std::string object to the print and len
functions - in fact, we often only have a C string that we want to
print or get the visual width of (that C string most often comes from
loc::gettext), and it's a bit wasteful to wrap it in a new std::string
object on every print/len call.

This does mean adding a few more .c_str()s, but there's not many places
where a std::string is being passed to these functions, and we already
use .c_str() sometimes.

-> Commit 1/3: font::print_wrap
   Commit 2/3: font::print
   Commit 3/3: font::len

desktop_version/src/Font.h

@@ -96,7 +96,7 @@ int print_wrap(
     uint32_t flags,
     int x,
     int y,
-    const std::string& text,
+    const char* text,
     uint8_t r, uint8_t g, uint8_t b,
     int linespacing = -1,
     int maxwidth = -1