[gdb] Fix more typos in comments

Fix typos in comments.  NFC.

Tested on x86_64-linux.

gdb/ChangeLog:

2019-10-18  Tom de Vries  <tdevries@suse.de>

	* aarch64-tdep.c: Fix typos in comments.
	* ada-lang.c: Same.
	* ada-tasks.c: Same.
	* alpha-tdep.c: Same.
	* alpha-tdep.h: Same.
	* amd64-nat.c: Same.
	* amd64-windows-tdep.c: Same.
	* arc-tdep.c: Same.
	* arc-tdep.h: Same.
	* arch-utils.c: Same.
	* arm-nbsd-tdep.c: Same.
	* arm-tdep.c: Same.
	* ax-gdb.c: Same.
	* blockframe.c: Same.
	* btrace.c: Same.
	* c-varobj.c: Same.
	* coff-pe-read.c: Same.
	* coffread.c: Same.
	* cris-tdep.c: Same.
	* darwin-nat.c: Same.
	* dbxread.c: Same.
	* dcache.c: Same.
	* disasm.c: Same.
	* dtrace-probe.c: Same.
	* dwarf-index-write.c: Same.
	* dwarf2-frame-tailcall.c: Same.
	* dwarf2-frame.c: Same.
	* dwarf2read.c: Same.
	* eval.c: Same.
	* exceptions.c: Same.
	* fbsd-tdep.c: Same.
	* findvar.c: Same.
	* frame.c: Same.
	* frv-tdep.c: Same.
	* gnu-v3-abi.c: Same.
	* go32-nat.c: Same.
	* h8300-tdep.c: Same.
	* hppa-tdep.c: Same.
	* i386-linux-tdep.c: Same.
	* i386-tdep.c: Same.
	* ia64-libunwind-tdep.c: Same.
	* ia64-tdep.c: Same.
	* infcmd.c: Same.
	* infrun.c: Same.
	* linespec.c: Same.
	* linux-nat.c: Same.
	* linux-thread-db.c: Same.
	* machoread.c: Same.
	* mdebugread.c: Same.
	* mep-tdep.c: Same.
	* mn10300-tdep.c: Same.
	* namespace.c: Same.
	* objfiles.c: Same.
	* opencl-lang.c: Same.
	* or1k-tdep.c: Same.
	* osabi.c: Same.
	* ppc-linux-nat.c: Same.
	* ppc-linux-tdep.c: Same.
	* ppc-sysv-tdep.c: Same.
	* printcmd.c: Same.
	* procfs.c: Same.
	* record-btrace.c: Same.
	* record-full.c: Same.
	* remote-fileio.c: Same.
	* remote.c: Same.
	* rs6000-tdep.c: Same.
	* s12z-tdep.c: Same.
	* score-tdep.c: Same.
	* ser-base.c: Same.
	* ser-go32.c: Same.
	* skip.c: Same.
	* sol-thread.c: Same.
	* solib-svr4.c: Same.
	* solib.c: Same.
	* source.c: Same.
	* sparc-nat.c: Same.
	* sparc-sol2-tdep.c: Same.
	* sparc-tdep.c: Same.
	* sparc64-tdep.c: Same.
	* stabsread.c: Same.
	* stack.c: Same.
	* symfile.c: Same.
	* symtab.c: Same.
	* target-descriptions.c: Same.
	* target-float.c: Same.
	* thread.c: Same.
	* utils.c: Same.
	* valops.c: Same.
	* valprint.c: Same.
	* value.c: Same.
	* varobj.c: Same.
	* windows-nat.c: Same.
	* xcoffread.c: Same.
	* xstormy16-tdep.c: Same.
	* xtensa-tdep.c: Same.

Change-Id: I5175f1b107bfa4e1cdd4a3361ccb4739e53c75c4

gdb/darwin-nat.c

@@ -2145,7 +2145,7 @@ darwin_nat_target::thread_alive (ptid_t ptid)
    copy it to RDADDR in gdb's address space.
    If WRADDR is not NULL, write gdb's LEN bytes from WRADDR and copy it
    to ADDR in inferior task's address space.
-   Return 0 on failure; number of bytes read / writen otherwise.  */
+   Return 0 on failure; number of bytes read / written otherwise.  */
 
 static int
 darwin_read_write_inferior (task_t task, CORE_ADDR addr,