make non-normative blocks unbreakable, add minor language clarifications

body.adoc

@@ -31,7 +31,7 @@ register.
 The miselect register implements at least enough bits to support all
 implemented miselect values (corresponding to the implemented extensions
 that utilize miselect/mireg* to indirectly access register state). The
-miselect register may be read-only zero If there are no extensions
+miselect register may be read-only zero if there are no extensions
 implemented that utilize it.
 
 Values of miselect with the most-significant bit set (bit XLEN - 1 = 1)
@@ -50,8 +50,7 @@ miselect._
 ====
 
 The behavior upon accessing mireg* from M-mode, while miselect holds a
-value that is reserved, or is standard but not implemented, is
-UNSPECIFIED.
+value that is not implemented, is UNSPECIFIED.
 
 [NOTE]
 [%unbreakable]
@@ -119,8 +118,7 @@ most-significant bit of siselect moves to the new position, retaining
 its value from before.
 
 The behavior upon accessing sireg* from M-mode or S-mode, while siselect
-holds a value that is reserved, or is standard but not implemented at
-supervisor level, is UNSPECIFIED.
+holds a value that is not implemented at supervisor level, is UNSPECIFIED.
 
 [NOTE]
 [%unbreakable]
@@ -222,10 +220,8 @@ A virtual instruction exception is raised for attempts from VS-mode or
 VU-mode to directly access vsiselect or vsireg*, or attempts from
 VU-mode to access siselect or sireg*.
 
-The behavior upon accessing vsireg* from M-mode or HS-mode, or accessing
-sireg* (really vsireg*) from VS-mode, while vsiselect holds a value that
-is reserved, or is standard but not implemented at HS level, is
-UNSPECIFIED.
+The behavior upon accessing vsireg* from M-mode or HS-mode, while vsiselect holds a value that is not implemented at HS level, is UNSPECIFIED.  Similarly, the behavior upon accessing sireg* (really vsireg*) from VS-mode, while vsiselect holds a value that is not implemented at VS level, is UNSPECIFIED.
+
 
 [NOTE]
 [%unbreakable]

intro.adoc

@@ -28,7 +28,7 @@ and indirectly accessible, the CSR's select value is unrelated to its
 CSR number._
 
 _Further, Machine-level and Supervisor-level select values are separate
-address spaces from each other. Although Machine-level and
+address spaces from each other; however, Machine-level and
 Supervisor-level CSRs with the same select value may be defined by an
 extension as partial or full aliases with respect to each other. This
 typically would be done for CSRs that can be delegated from