src/bin/sh: Fix spelling errors

Pull Request: https://github.com/freebsd/freebsd-src/pull/544
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>

bin/sh/error.c

@@ -74,7 +74,7 @@ static void verrorwithstatus(int, const char *, va_list) __printf0like(2, 0) __d
  * just do a longjmp to the exception handler.  The type of exception is
  * stored in the global variable "exception".
  *
- * Interrupts are disabled; they should be reenabled when the exception is
+ * Interrupts are disabled; they should be re-enabled when the exception is
  * caught.
  */
 

bin/sh/eval.c

@@ -900,7 +900,7 @@ evalcommand(union node *cmd, int flags, struct backcmd *backcmd)
 				 * the hash table isn't filled with items
 				 * from the temporary setting.
 				 *
-				 * It would be better to forbit using and
+				 * It would be better to forbid using and
 				 * updating the table while this command
 				 * runs, by the command finding mechanism
 				 * is heavily integrated with hash handling,

bin/sh/nodetypes

@@ -64,7 +64,7 @@ NPIPE npipe			# a pipeline
 	backgnd	  int			# set to run pipeline in background
 	cmdlist	  nodelist		# the commands in the pipeline
 
-NREDIR nredir			# redirection (of a compex command)
+NREDIR nredir			# redirection (of a complex command)
 	type	  int
 	n	  nodeptr		# the command
 	redirect  nodeptr		# list of file redirections

bin/sh/shell.h

@@ -55,7 +55,7 @@
 /* #define DEBUG 1 */
 
 /*
- * Type of used arithmetics. SUSv3 requires us to have at least signed long.
+ * Type of used arithmetic. SUSv3 requires us to have at least signed long.
  */
 typedef intmax_t arith_t;
 #define	ARITH_FORMAT_STR  "%" PRIdMAX