[NFC][analyzer][docs] Migrate 'annotations.html' to RST (#122246)

This commit migrates the contents of 'annotations.html' in the old
HTML-based documentation of the Clang static analyzer to the new
RST-based documentation.

During this conversion I reordered the sections of this documentation
file by placing the section "Custom Assertion Handlers" as a subsection
of "Annotations to Enhance Generic Checks". (The primary motivation was
that Sphinx complained about inconsistent section levels; with this
change I preserved that sections describing individual annotations are
all on the same level.)

Apart from this change and the format conversion, I didn't review,
validate or edit the contents of this documentation file because I think
it would be better to place any additional changes in separate commits.

Author: NagyDonat

clang/docs/LanguageExtensions.rst

@@ -2137,8 +2137,8 @@ method; it specifies that the method expects its ``self`` parameter to have a
   - (void) bar __attribute__((ns_consumes_self));
   - (void) baz:(id) __attribute__((ns_consumed)) x;
 
-Further examples of these attributes are available in the static analyzer's `list of annotations for analysis
-<https://clang-analyzer.llvm.org/annotations.html#cocoa_mem>`_.
+Further examples of these attributes are available in the static analyzer's
+`list of annotations for analysis <analyzer/user-docs/Annotations.html#cocoa-mem>`__.
 
 Query for these features with ``__has_attribute(ns_consumed)``,
 ``__has_attribute(ns_returns_retained)``, etc.
@@ -4792,8 +4792,8 @@ Extensions for Static Analysis
 Clang supports additional attributes that are useful for documenting program
 invariants and rules for static analysis tools, such as the `Clang Static
 Analyzer <https://clang-analyzer.llvm.org/>`_. These attributes are documented
-in the analyzer's `list of source-level annotations
-<https://clang-analyzer.llvm.org/annotations.html>`_.
+in the analyzer's `list of annotations for analysis
+<analyzer/user-docs/Annotations.html>`__.
 
 
 Extensions for Dynamic Analysis

clang/docs/UsersManual.rst

@@ -1364,10 +1364,8 @@ Controlling Static Analyzer Diagnostics
 While not strictly part of the compiler, the diagnostics from Clang's
 `static analyzer <https://clang-analyzer.llvm.org>`_ can also be
 influenced by the user via changes to the source code. See the available
-`annotations <https://clang-analyzer.llvm.org/annotations.html>`_ and the
-analyzer's `FAQ
-page <https://clang-analyzer.llvm.org/faq.html#exclude_code>`_ for more
-information.
+`annotations <analyzer/user-docs/Annotations.html>`_ and the analyzer's
+`FAQ page <analyzer/user-docs/FAQ.html#exclude-code>`_ for more information.
 
 .. _usersmanual-precompiled-headers:
 

clang/www/analyzer/images/example_attribute_nonnull.png renamed to clang/docs/analyzer/images/example_attribute_nonnull.png

@@ -12,4 +12,5 @@ Contents:
    user-docs/FilingBugs
    user-docs/CrossTranslationUnit
    user-docs/TaintAnalysisConfiguration
+   user-docs/Annotations
    user-docs/FAQ