GNUmakefile: add spellfix target, use it. (#4387)

TODO: Remove the go.mod/go.sum in internal/tools once doing so doesn't break CI (e.g. once we drop support for go 1.19)

* builder/cc1as.h: fix typo found by 'make spell'
* GNUmakefile: remove exception for inbetween, fix instance now found by 'make spell'
* GNUmakefile: remove exception for programmmer, fix instance now found by 'make spell'
* go.mod: use updated misspell. GNUmakefile: add spellfix target, use it.
* ignore directories properly when invoking spellchecker.
* make spell: give internal/tools its own go.mod, as misspell requires newer go
* make lint: depend on tools and run the installed revive
(which was perhaps implied by the change that added revive to internal/tools,
but not required in GNUmakefile until we gave internal/tools its own temporary go.mod)
* .github: now that 'make spell' works well, run it from CI
* GNUmakefile: make spell now aborts if it finds misspelt words, so what it finds doesn't get lost in CI logs
* GNUmakefile: tools: avoid -C option on go generate to make test-llvm15-go119 circleci job happy, see
https://cs.opensource.google/go/go/+/2af48cbb7d85e5fdc635e75b99f949010c607786
* internal/tools/go.mod: fix format of go version to leave out patchlevel, else go complains.

src/machine/machine_esp32c3.go

@@ -480,7 +480,7 @@ func (uart *UART) enableTransmitter() {
 	uart.Bus.SetCONF0_TXFIFO_RST(0)
 	// TXINFO empty threshold is when txfifo_empty_int interrupt produced after the amount of data in Tx-FIFO is less than this register value.
 	uart.Bus.SetCONF1_TXFIFO_EMPTY_THRHD(uart_empty_thresh_default)
-	// we are not using interrut on TX since write we are waiting for FIFO to have space.
+	// we are not using interrupt on TX since write we are waiting for FIFO to have space.
 	// uart.Bus.INT_ENA.SetBits(esp.UART_INT_ENA_TXFIFO_EMPTY_INT_ENA)
 }