util/StringUtil: rename strchug_fast_c() to strchug_fast()

Overload the name.

src/PlaylistDatabase.cxx

@@ -59,7 +59,7 @@ playlist_metadata_load(TextFile &file, PlaylistVector &pv, const char *name,
 		}
 
 		*colon++ = 0;
-		value = strchug_fast_c(colon);
+		value = strchug_fast(colon);
 
 		if (strcmp(line, "mtime") == 0)
 			pm.mtime = strtol(value, nullptr, 10);

src/SongSave.cxx

@@ -78,7 +78,7 @@ song_load(TextFile &file, Directory *parent, const char *uri,
 		}
 
 		*colon++ = 0;
-		value = strchug_fast_c(colon);
+		value = strchug_fast(colon);
 
 		if ((type = tag_name_parse(line)) != TAG_NUM_OF_ITEM_TYPES) {
 			tag.AddItem(type, value);

src/playlist/ExtM3uPlaylistPlugin.cxx

@@ -85,7 +85,7 @@ extm3u_parse_tag(const char *line)
 		/* 0 means unknown duration */
 		duration = 0;
 
-	name = strchug_fast_c(endptr + 1);
+	name = strchug_fast(endptr + 1);
 	if (*name == 0 && duration == 0)
 		/* no information available; don't allocate a tag
 		   object */

src/util/StringUtil.cxx

@@ -24,7 +24,7 @@
 #include <assert.h>
 
 const char *
-strchug_fast_c(const char *p)
+strchug_fast(const char *p)
 {
 	while (*p != 0 && g_ascii_isspace(*p))
 		++p;

src/util/StringUtil.hxx

@@ -31,16 +31,13 @@
  */
 gcc_pure
 const char *
-strchug_fast_c(const char *p);
+strchug_fast(const char *p);
 
-/**
- * Same as strchug_fast_c(), but works with a writable pointer.
- */
 gcc_pure
 static inline char *
 strchug_fast(char *p)
 {
-	return const_cast<char *>(strchug_fast_c(p));
+	return const_cast<char *>(strchug_fast((const char *)p));
 }
 
 /**