Add params support for aliases

Before aliases used spaces in their name,
now the alias part is being read only before the first space,
thus allowing execution of complex command with aliases.

Example (with plugin):
`/alias add echo "/system exec echo"`
will allow execution of
`/echo test`
as opposed to prior state when the Profanity will
search for alias "echo tests" and output `Unknown command: /echo test`

Minor change: removed an example with invalid command (`/away`)

src/command/cmd_funcs.c

@@ -5091,6 +5091,10 @@ cmd_alias(ProfWin* window, const char* const command, gchar** args)
             cons_bad_cmd_usage(command);
             return TRUE;
         } else {
+            if (strchr(alias, ' ')) {
+                cons_bad_cmd_usage(command);
+                return TRUE;
+            }
             char* alias_p = alias;
             GString* ac_value = g_string_new("");
             if (alias[0] == '/') {
@@ -8565,15 +8569,20 @@ _cmd_execute_alias(ProfWin* window, const char* const inp, gboolean* ran)
     }
 
     auto_char char* alias = strdup(inp + 1);
-    auto_gchar gchar* value = prefs_get_alias(alias);
-    if (value) {
-        *ran = TRUE;
-        gboolean result = cmd_process_input(window, value);
-        return result;
+    auto_gcharv char** alias_parts = g_strsplit(alias, " ", 2);
+    auto_gchar gchar* value = prefs_get_alias(alias_parts[0]);
+
+    if (!value) {
+        *ran = FALSE;
+        return TRUE;
     }
 
-    *ran = FALSE;
-    return TRUE;
+    char* params = alias_parts[1];
+    auto_gchar gchar* full_cmd = params ? g_strdup_printf("%s %s", value, params) : g_strdup(value);
+
+    *ran = TRUE;
+    gboolean result = cmd_process_input(window, full_cmd);
+    return result;
 }
 
 // helper function for status change commands