QROCDE/UPNQR: add FAST_MODE (try 4 not 8 masks automatically)

docs/manual.pmd

@@ -2097,9 +2097,9 @@ Value               Effect
 `HEIGHTPERROW_MODE` Interpret the `height` variable as per-row rather than as
                     overall height.
 
-`FAST_MODE`         Use faster if less optimal encodation for symbologies that
-                    support it (currently `DATAMATRIX`, `MICROPDF417` and
-                    `PDF417` only).
+`FAST_MODE`         Use faster if less optimal encodation or other shortcuts if
+                    available (affects `DATAMATRIX`, `MICROPDF417`, `PDF417`,
+                    `QRCODE` and `UPNQR` only).
 --------------------------------------------------------------------------------
 
 Table: API `input_mode` Values {#tbl:api_input_mode tag="$ $"}
@@ -3608,6 +3608,10 @@ by using the `--mask` switch with values 0-7, or in the API by setting
 option_3 = ZINT_FULL_MULTIBYTE | (N + 1) << 8
 ```
 
+The `--fast` option (API `input_mode |= FAST_MODE`) may be used when leaving
+Zint to automatically select a mask to reduce the number of masks to try to four
+(0, 2, 4, 7).
+
 QR Code supports Structured Append of up to 16 symbols and a numeric ID
 (parity), which can be set by using the `--structapp` option (see [4.16
 Structured Append]) (API `structapp`). The parity ID ranges from 0 (default) to
@@ -3738,6 +3742,8 @@ The following example creates a symbol from data saved as a Latin-2 file:
 zint -o upnqr.png -b 143 --scale=3 --binary -i upn.txt
 ```
 
+A mask may be manually specified or the `--fast` option used as with QRCODE.
+
 ### 6.6.6 MaxiCode (ISO 16023)
 
 ![`zint -b MAXICODE -d "1Z00004951\GUPSN\G06X610\G159\G1234567\G1/1\G\GY\G1 MAIN