[r6rs-discuss] Couple of typos/tweaks in 7.1

[Ben Goetter]

R5.96 7.1: "An <import level> is one of the following:
 run
 expand
 (meta <level>)
where <level> represents an exact integer object."  Since a negative 
phase is meaningless, this should probably specify <level> as an exact 
nonnegative integer object.

Also, near the end of the section: "The names /library/, /export/, 
/import/, /for/, /run/, /expand/, /meta/, /import/, /export/, /only/, 
/except/, /prefix/, /rename/, /and/, /or/, />=/, and /<=/ appearing in 
the library syntax are part of the syntax and are not reserved, [...]"  
This should also include the name /not/ as part of the syntax and not 
reserved.

Ben