docs: Fix up new instances of index reordering

This commit fixes up an instance of the index entry mis-ordering that
occurred between the formulation and application of commit
r13-6310-gf33d7a88d069d1.

gcc/ChangeLog:

	* doc/extend.texi: Associate use_hazard_barrier_return index
	entry with its attribute.
	* doc/invoke.texi: Associate -fcanon-prefix-map index entry with
	its attribute

gcc/doc/extend.texi

@@ -5662,8 +5662,8 @@ to locally turn off MIPS16 and microMIPS code generation.  This attribute
 overrides the @option{-mips16} and @option{-mmicromips} options on the
 command line (@pxref{MIPS Options}).
 
-@item use_hazard_barrier_return
 @cindex @code{use_hazard_barrier_return} function attribute, MIPS
+@item use_hazard_barrier_return
 This function attribute instructs the compiler to generate a hazard barrier
 return that clears all execution and instruction hazards while returning,
 instead of generating a normal return instruction.
@@ -24877,8 +24877,8 @@ fine-grained control when necessary. It is also the most portable
 alternative and programs using this approach will work with most modern
 compilers.
 
-@item
 @opindex fno-implicit-templates
+@item
 Compile your code with @option{-fno-implicit-templates} to disable the
 implicit generation of template instances, and explicitly instantiate
 all the ones you use.  This approach requires more knowledge of exactly

gcc/doc/invoke.texi

@@ -2211,8 +2211,8 @@ directives are not affected by these options.  See also
 @option{-fmacro-prefix-map}, @option{-fdebug-prefix-map},
 @option{-fprofile-prefix-map} and @option{-fcanon-prefix-map}.
 
-@item -fcanon-prefix-map
 @opindex fcanon-prefix-map
+@item -fcanon-prefix-map
 For the @option{-f*-prefix-map} options normally comparison
 of @file{@var{old}} prefix against the filename that would be normally
 referenced in the result of the compilation is done using textual