docs: move asm-annotations.rst into core-api

This one file should not really be in the top-level documentation
directory. core-api/ may not be a perfect fit but seems to be best, so
move it there. Adjust a couple of internal document references to make
them location-independent, and point checkpatch.pl at the new location.

Cc: Jiri Slaby <[e-mail]>
Cc: Joe Perches <[e-mail]>
Reviewed-by: David Vernet <[e-mail]>
Acked-by: Jani Nikula <[e-mail]>
Signed-off-by: Jonathan Corbet <[e-mail]>
Acked-by: Randy Dunlap <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jonathan Corbet <[e-mail]>

Documentation/asm-annotations.rst Documentation/core-api/asm-annotations.rst

···
 information. In particular, on properly annotated objects, ``objtool`` can be
 run to check and fix the object if needed. Currently, ``objtool`` can report
 missing frame pointer setup/destruction in functions. It can also
-automatically generate annotations for :doc:`ORC unwinder <x86/orc-unwinder>`
+automatically generate annotations for the ORC unwinder
+(Documentation/x86/orc-unwinder.rst)
 for most code. Both of these are especially important to support reliable
-stack traces which are in turn necessary for :doc:`Kernel live patching
-<livepatch/livepatch>`.
+stack traces which are in turn necessary for kernel live patching
+(Documentation/livepatch/livepatch.rst).
 
 Caveat and Discussion
 ---------------------

Documentation/core-api/index.rst

···
    printk-formats
    printk-index
    symbol-namespaces
+   asm-annotations
 
 Data structures and low-level utilities
 =======================================

Documentation/index.rst

···
    devicetree/index
 
 
-Architecture-agnostic documentation
------------------------------------
-
-.. toctree::
-   :maxdepth: 1
-
-   asm-annotations
-
 Architecture-specific documentation
 -----------------------------------
 

scripts/checkpatch.pl

···
 		if ($realfile =~ /\.S$/ &&
 		    $line =~ /^\+\s*(?:[A-Z]+_)?SYM_[A-Z]+_(?:START|END)(?:_[A-Z_]+)?\s*\(\s*\.L/) {
 			WARN("AVOID_L_PREFIX",
-			     "Avoid using '.L' prefixed local symbol names for denoting a range of code via 'SYM_*_START/END' annotations; see Documentation/asm-annotations.rst\n" . $herecurr);
+			     "Avoid using '.L' prefixed local symbol names for denoting a range of code via 'SYM_*_START/END' annotations; see Documentation/core-api/asm-annotations.rst\n" . $herecurr);
 		}
 
 # check we are in a valid source file C or perl if not then ignore this hunk