[DOC] Refactor Functions section in LangRef

[speryt]

Summary

This change is a small refactor of Functions section
to update placement of define syntax.

[RKSimon]

LGTM - cheers

[speryt]

@RKSimon could you please merge this diff? I don't have required permissions to do so. Thanks!

llvm/docs/LangRef.rst

 optional :ref:`linkage type <linkage>`, an optional :ref:`runtime preemption
 specifier <runtime_preemption_model>`,  an optional :ref:`visibility
 style <visibility>`, an optional :ref:`DLL storage class <dllstorageclass>`,
 an optional :ref:`calling convention <callingconv>`,
 an optional ``unnamed_addr`` attribute, a return type, an optional
 :ref:`parameter attribute <paramattrs>` for the return type, a function
 name, a (possibly empty) argument list (each with optional :ref:`parameter
 attributes <paramattrs>`), optional :ref:`function attributes <fnattrs>`,
-an optional address space, an optional section, an optional alignment,
-an optional :ref:`comdat <langref_comdats>`,
+an optional address space, an optional section, an optional partition,
+an optional alignment, an optional :ref:`comdat <langref_comdats>`,
 an optional :ref:`garbage collector name <gc>`, an optional :ref:`prefix <prefixdata>`,
 an optional :ref:`prologue <prologuedata>`,
 an optional :ref:`personality <personalityfn>`,
 an optional list of attached :ref:`metadata <metadata>`,
 an opening curly brace, a list of basic blocks, and a closing curly brace.
 
+Syntax::
+
+    define [linkage] [PreemptionSpecifier] [visibility] [DLLStorageClass]
+           [cconv] [ret attrs]
+           <ResultType> @<FunctionName> ([argument list])
+           [(unnamed_addr|local_unnamed_addr)] [AddrSpace] [fn Attrs]
+           [section "name"] [partition "name"] [comdat [($name)]] [align N]
+           [gc] [prefix Constant] [prologue Constant] [personality Constant]
+           (!name !N)* { ... }
+
+The argument list is a comma separated sequence of arguments where each
+argument is of the following form:
+
+Syntax::
+
+   <type> [parameter Attrs] [name]
+
 LLVM function declarations consist of the "``declare``" keyword, an
 optional :ref:`linkage type <linkage>`, an optional :ref:`visibility style
 <visibility>`, an optional :ref:`DLL storage class <dllstorageclass>`, an
 optional :ref:`calling convention <callingconv>`, an optional ``unnamed_addr``
 or ``local_unnamed_addr`` attribute, an optional address space, a return type,
 an optional :ref:`parameter attribute <paramattrs>` for the return type, a function name, a possibly
 empty list of arguments, an optional alignment, an optional :ref:`garbage
 collector name <gc>`, an optional :ref:`prefix <prefixdata>`, and an optional

 be significant and two identical functions can be merged.
 
 If the ``local_unnamed_addr`` attribute is given, the address is known to
 not be significant within the module.
 
 If an explicit address space is not given, it will default to the program
 address space from the :ref:`datalayout string<langref_datalayout>`.
 
-Syntax::
-
-    define [linkage] [PreemptionSpecifier] [visibility] [DLLStorageClass]
-           [cconv] [ret attrs]
-           <ResultType> @<FunctionName> ([argument list])
-           [(unnamed_addr|local_unnamed_addr)] [AddrSpace] [fn Attrs]
-           [section "name"] [partition "name"] [comdat [($name)]] [align N]
-           [gc] [prefix Constant] [prologue Constant] [personality Constant]
-           (!name !N)* { ... }
-
-The argument list is a comma separated sequence of arguments where each
-argument is of the following form:
-
-Syntax::
-
-   <type> [parameter Attrs] [name]
-
-
 .. _langref_aliases:
 
 Aliases
 -------
 
 Aliases, unlike function or variables, don't create any new data. They
 are just a new symbol and metadata for an existing position.