Move sign-extension-ops before saturating truncation ops. (#1192)

Address comment in #1144 (comment).

Author: ngzhian

document/core/binary/instructions.rst

@@ -374,6 +374,16 @@ All other numeric instructions are plain opcodes without any immediates.
      \hex{BF} &\Rightarrow& \F64.\REINTERPRET\K{\_}\I64 \\
    \end{array}
 
+.. math::
+   \begin{array}{llclll}
+   \phantom{\production{instruction}} & \phantom{\Binstr} &\phantom{::=}& \phantom{\dots} && \phantom{thisshouldbeenough} \\[-2ex] &&|&
+     \hex{C0} &\Rightarrow& \I32.\EXTEND\K{8\_s} \\ &&|&
+     \hex{C1} &\Rightarrow& \I32.\EXTEND\K{16\_s} \\ &&|&
+     \hex{C2} &\Rightarrow& \I64.\EXTEND\K{8\_s} \\ &&|&
+     \hex{C3} &\Rightarrow& \I64.\EXTEND\K{16\_s} \\ &&|&
+     \hex{C4} &\Rightarrow& \I64.\EXTEND\K{32\_s} \\
+   \end{array}
+
 .. _binary-cvtop-trunc-sat:
 
 The saturating truncation instructions all have a one byte prefix.
@@ -392,17 +402,6 @@ The saturating truncation instructions all have a one byte prefix.
    \end{array}
 
 
-.. math::
-   \begin{array}{llclll}
-   \phantom{\production{instruction}} & \phantom{\Binstr} &\phantom{::=}& \phantom{\dots} && \phantom{thisshouldbeenough} \\[-2ex] &&|&
-     \hex{C0} &\Rightarrow& \I32.\EXTEND\K{8\_s} \\ &&|&
-     \hex{C1} &\Rightarrow& \I32.\EXTEND\K{16\_s} \\ &&|&
-     \hex{C2} &\Rightarrow& \I64.\EXTEND\K{8\_s} \\ &&|&
-     \hex{C3} &\Rightarrow& \I64.\EXTEND\K{16\_s} \\ &&|&
-     \hex{C4} &\Rightarrow& \I64.\EXTEND\K{32\_s} \\
-   \end{array}
-
-
 .. index:: expression
    pair: binary format; expression
    single: expression; constant