[PATCH, wwwdocs] Record diagnosing of r2 clobbers for PowerPC

[Bill Schmidt]

Hi,

Following committed to wwwdocs per discussion in PR78095.

Thanks,
Bill

Index: htdocs/gcc-7/changes.html                                                
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RCS file: /cvs/gcc/wwwdocs/htdocs/gcc-7/changes.html,v                          
retrieving revision 1.19                                                        
diff -r1.19 changes.html                                                        
375a376,378
>   <li>GCC now diagnoses inline assembly that clobbers register r2.            
>     This has always been invalid code, and is no longer quietly               
>     tolerated.</li>