[skip ci] docs: cross reference tables from manual (#3656)

* docs/reference-manual: link to references tables

Currently the reference manual entries for *machine.cpu_family() and
*machine.system() have incomplete (and wrong) information. Rather than
continue to duplicate this information just link to the reference
tables.

* docs/Reference-manual: fix link target

The IDs in hotdoc are always lowered, so this pointed to the right page,
but didn't go to the heading.

* docs/Reference-manual: link compiler.get_id directly to tables

Currently it goes round about to an entry that doesn't add much
information and points to the reference table. Instead just point to the
reference table.

docs/markdown/Reference-manual.md

@@ -1423,7 +1423,7 @@ the following methods.
   the string to an array if needed.
 
 - `override_find_program(progname, program)` [*(Added
-  0.46.0)*](Release-notes-for-0-46-0.html#Can-override-find_program)
+  0.46.0)*](Release-notes-for-0-46-0.html#can-override-find_program)
   specifies that whenever `find_program` is used to find a program
   named `progname`, Meson should not not look it up on the system but
   instead return `program`, which may either be the result of
@@ -1444,17 +1444,15 @@ doing the actual compilation. See
 [Cross-compilation](Cross-compilation.md). It has the following
 methods:
 
-- `cpu_family()` returns the CPU family name. Guaranteed to return
-  `x86` for 32-bit userland on x86 CPUs, `x86_64` for 64-bit userland
-  on x86 CPUs, `arm` for 32-bit userland on all ARM CPUs, etc.
+- `cpu_family()` returns the CPU family name. [This table](Reference-tables.md#cpu-families)
+  contains all known CPU families. These are guaranteed to continue working.
 
 - `cpu()` returns a more specific CPU name, such as `i686`, `amd64`,
   etc.
 
-- `system()` returns the operating system name, such as `windows` (all
-  versions of Windows), `linux` (all Linux distros), `darwin` (all
-  versions of OS X/macOS), `cygwin` (for Cygwin), and `bsd` (all *BSD
-  OSes).
+- `system()` returns the operating system name.
+  [This table](Reference-tables.html#operating-system-names) Lists all of the
+  currently known Operating System names, these are guaranteed to continue working.
 
 - `endian()` returns `big` on big-endian systems and `little` on
   little-endian systems.
@@ -1464,7 +1462,7 @@ Currently, these values are populated using
 and
 [`platform.machine()`](https://docs.python.org/3.4/library/platform.html#platform.machine). If
 you think the returned values for any of these are incorrect for your
-system or CPU, or if your OS is not in the above list, please file [a
+system or CPU, or if your OS is not in the linked table, please file [a
 bug report](https://github.com/mesonbuild/meson/issues/new) with
 details and we'll look into it.
 
@@ -1544,7 +1542,7 @@ the following methods:
   value as a string or empty string if it is not defined.
 
 - `get_id()` returns a string identifying the compiler. For example,
-  `gcc`, `msvc`, [and more](Compiler-properties.md#compiler-id).
+  `gcc`, `msvc`, [and more](Reference-tables.html#compiler-ids).
 
 - `get_supported_arguments(list_of_string)` *(added 0.43.0)* returns
   an array containing only the arguments supported by the compiler,