Command taintmem does not appear in list of commands when help is typed.

[JamesTimothyMeech]

Describe the bug
Command taintmem does not appear in list of commands when help is typed.

To Reproduce

ADDVALUETRACE           BATTALERTFRAC           BATTCF                  
	BATTETALUT              BATTETALUTNENTRIES      BATTILEAK               
	BATTINOMINAL            BATTNODEATTACH          BATTRF                  
	BATTSTATS               BATTVBATTLUT            BATTVBATTLUTNENTRIES    
	BATTVLOSTLUT            BATTVLOSTLUTNENTRIES    BPT                     
	BPTDEL                  BPTLS                   C                       
	CA                      CACHEINIT               CACHEOFF                
	CACHESTATS              CD                      CLOCKINTR               
	CONT                    D                       DEFNDIST                
	DELVALUETRACE           DUMPALL                 DUMPDISTR               
	DUMPMEM                 DUMPPIPE                DUMPREGS                
	DUMPSYSREGS             DUMPTLB                 DYNINSTR                
	EBATTINTR               EFAULTS                 FF                      
	FILE2NETSEG             FLTTHRESH               FORCEAVGPWR             
	GETRANDOMSEED           HELP                    HWSEEREG                
	IGN                     INITRANDTABLE           INITSEESTATE            
	L                       LISTRVARS               LOAD                    
	LOCSTATS                MALLOCDEBUG             MAN                     
	MMAP                    N                       NANOPAUSE               
	ND                      NETCORREL               NETDEBUG                
	NETNEWSEG               NETNODENEWIFC           NETSEG2FILE             
	NETSEGDELETE            NETSEGFAILDURMAX        NETSEGFAILPROB          
	NETSEGFAILPROBFN        NETSEGNICATTACH         NETSEGPROPMODEL         
	NEWBATT                 NEWNODE                 NI                      
	NODEFAILDURMAX          NODEFAILPROB            NODEFAILPROBFN          
	NODETACH                NUMAREGION              NUMASETMAPID            
	NUMASTATS               NUMASTATSALL            OFF                     
	ON                      PARSEOBJDUMP            PAUINFO                 
	PAUSE                   PCBT                    PD                      
	PE                      PF                      PFUN                    
	PI                      POWERSTATS              POWERTOTAL              
	PS                      PWD                     Q                       
	QUIT                    R                       RANDPRINT               
	RATIO                   REGISTERRVAR            REGISTERSTABS           
	RENUMBERNODES           RESETALLCTRS            RESETCPU                
	RESETNODECTRS           RETRYALG                RUN                     
	SAVE                    SENSORSDEBUG            SETBASENODEID           
	SETBATT                 SETBATTFEEDPERIOD       SETDUMPPWRPERIOD        
	SETFAULTPERIOD          SETFLASHRLATENCY        SETFLASHWLATENCY        
	SETFREQ                 SETIFCOUI               SETLOC                  
	SETMEMBASE              SETMEMRLATENCY          SETMEMWLATENCY          
	SETNETPERIOD            SETNODE                 SETNODEMASS             
	SETPC                   SETPHYSICSPERIOD        SETPROPULSIONCOEFFS     
	SETQUANTUM              SETRANDOMSEED           SETSCALEALPHA           
	SETSCALEK               SETSCALEVT              SETSCHEDRANDOM          
	SETSCHEDROUNDROBIN      SETTIMERDELAY           SETVDD                  
	SFATAL                  SHAREBUS                SHOWCLK                 
	SHOWMEMBASE             SHOWPIPE                SIGSRC                  
	SIGSUBSCRIBE            SIZEMEM                 SIZEPAU                 
	SPLIT                   SRECL                   STOP                    
	THROTTLE                THROTTLEWIN             TRACE                   
	V                       VALUESTATS              VERBOSE                 
	VERSION                 
There are 143 commands and 14 aliases:
Type "man <command>" for help on a particular command.
You can also type "man <cmd>*" to get a list of commands matching "cmd".
[ID=0 of 1][PC=0x8000000][3.3E+00V, 6.0E+01MHz] ```

**Expected behavior**
taintmem should show in this list

**Screenshots**
If applicable, add screenshots to help explain your problem.

**Host OS (please complete the following information):**
 - OS: (e.g., macOS 10.9).
 - Browser (e.g., Chrome or Safari).
 - Version (e.g., 22).

**You local changes (please complete the following information):**
 - Output of `git diff`.
- Output of `git remote -v`.

**Additional context**
Add any other context about the problem here.

[SamuelmsWong-zz]

grep through all the mk* files and replace any occurrences of lex-hitachi-sh.c with lex-riscv.c.
Alternatively copy all the taint instructions from lex-riscv.c into lex-hitachi-sh.c
Reason: There is an undesired duplication of code in lex-riscv.c and lex-hitachi-sh.c, so all changes to one should be reflected in the other. This should be recorded as an issue or in the files themselves if not fixed.

[phillipstanleymarbell]

Related to #125, #127, #129.