more fixes

Author: topperc

README.mkd

@@ -67,7 +67,7 @@ rules and more extensions added into RISC-V, the canonical order is non-obvious
 to humans, so tools should accept the ISA string in non-canonical order to reduce
 the burden of remembering the canonical order.
 
-Detail rule for ISA string:
+Detail rules for ISA string:
 
 1. First letter must be `i`, `e` or `g`.
 2. Single-letter may be non-canonical order.
@@ -94,12 +94,12 @@ If the 'C' (compressed) instruction set extension is targeted, the compiler
 will generate compressed instructions where possible.
 
 NOTE: Single-letter extension with version (e.g. `m2p0`) is still treated as
-      a single-letter extension, we won't treat it as multi-letter extension.
+      a single-letter extension, it won't be treated as a multi-letter extension.
 
 NOTE: Any output of ISA string like `Tag_RISCV_arch` must be canonical order.
 
 NOTE: Cross-tool argument are highly recommended to be passed in canonical order
-      for backward compatible.
+      for backward compatibility.
 
 ### Issues for consideration
 * Whether `riscv32` and `riscv64` should be accepted as synonyms for `rv32`