basic/glyph-util: rename "special glyph" to just "glyph"

Admittedly, some of our glyphs _are_ special, e.g. "O=" for SPECIAL_GLYPH_TOUCH ;)
But we don't need this in the name. The very long names make some invocations
very wordy, e.g. special_glyph(SPECIAL_GLYPH_SLIGHTLY_UNHAPPY_SMILEY).
Also, I want to add GLYPH_SPACE, which is not special at all.

src/basic/chase.c

@@ -41,7 +41,7 @@ static int log_unsafe_transition(int a, int b, const char *path, ChaseFlags flag
 
         return log_warning_errno(SYNTHETIC_ERRNO(ENOLINK),
                                  "Detected unsafe path transition %s (owned by %s) %s %s (owned by %s) during canonicalization of %s.",
-                                 strna(n1), strna(user_a), special_glyph(SPECIAL_GLYPH_ARROW_RIGHT), strna(n2), strna(user_b), path);
+                                 strna(n1), strna(user_a), glyph(GLYPH_ARROW_RIGHT), strna(n2), strna(user_b), path);
 }
 
 static int log_autofs_mount_point(int fd, const char *path, ChaseFlags flags) {