metadata/code: remove syntax section and integrate with the binary section

Author: yuri91

document/metadata/code/binary.rst

@@ -8,6 +8,10 @@ Binary Format
 Code Metadata
 -------------
 
+A Code Metadata item is a piece of information logically attached to an instruction.
+
+An item is associated with a format, which defines the item's payload.
+
 All code metadata items of a format named *T* are grouped under a custom section
 named *'metadata.code.T'*.
 The following parametrized grammar rules define the generic structure of a code metadata
@@ -30,14 +34,19 @@ section of format *T*.
 
 Where :math:`\X{off}` is the byte offset of the annotation starting from the beginning of the function body, and :math:`\X{data}` is a further payload, whose content depends on the format :math:`T`.
 
-*code metadata function* entries must appear in order of increasing *function id*, and duplicate id values are not allowed. *code metadata item* entries must appear in order of increasing *instruction offset*, and duplicate offset values are not allowed.
+|Bcodemetadatafunc| entries must appear in order of increasing :math:`x`, and duplicate id values are not allowed. |Bcodemetadata| entries must appear in order of increasing :math:`\X{off}`, and duplicate offset values are not allowed.
 
 .. _binary-branchhints:
 
 Branch Hints
 ~~~~~~~~~~~~
 
-A Branch Hint is code metadata item with format *branch_hint*.
+A Branch Hint is a code metadata item with format *branch_hint*.
+
+It can only be attached to |BRIF| and |IF| instructions.
+
+Its payload indicates whether the branch is likely or unlikely to be taken.
+
 All branch hints for a module are contained in a single code metadata section
 with name *'metadata.code.branch_hint'*.
 
@@ -55,3 +64,6 @@ with name *'metadata.code.branch_hint'*.
    \end{array}
 .. index:: ! branch hint section
 
+A value of |Blikely| means that the branch is likely to be taken, while a
+value of |Bunlikely| means the opposite. A branch with no hints is considered
+equally likely to be taken or not.

document/metadata/code/index.rst

@@ -11,6 +11,5 @@ WebAssembly Code Metadata
    :maxdepth: 1
 
    intro
-   syntax
    binary
    text