fix: include ~= and === in text

Signed-off-by: Henry Schreiner <[email protected]>

Author: henryiii

source/specifications/dependency-specifiers.rst

@@ -201,10 +201,14 @@ The variables marked with ``Version`` or ``Version | String`` use the version
 comparison rules of the :ref:`Version specifier specification
 <version-specifiers>` when those are defined (that is when both sides have a
 valid version specifier). If either side is not expressible as a ``Version``,
-then ``>=``, and ``<=`` only check for exact equality; no ordering is assumed.
-On other operators, operators perform the same as they do for strings or sets
-in Python based on whether the marker value is a string or set itself.
-Otherwise an error should be raised. e.g. the following will result in errors::
+then ``>=`` and``<=``, are equivalent to ``==``; no ordering is
+assumed.  The ``<`` and ``>`` operators always return false on strings. The
+``===`` legacy arbitrary equivalence operator does an exact, case insensitive
+comparison regardless of if a string fallback is used.  On other operators,
+operators perform the same as they do for strings or sets in Python based on
+whether the marker value is a string or set itself.  Otherwise an error should
+be raised; it should be noted that ``~=`` does not support string fallback.
+e.g. the following will result in errors::
 
     "dog" ~= "fred"
     python_version ~= "surprise"
@@ -214,7 +218,8 @@ ordered comparison operators may also follow same rules as ``Version`` defined
 above when one side is not a valid Version, with ``>=`` and ``<=`` being
 equivalent to ``==``, and ``<`` and ``>`` always evaluating to ``False``. This
 is legacy behavior due to an older version of this spec, and tools may choose
-to warn or fail if ordered comparisons are used on ``String`` markers.
+to warn or fail if ordered comparisons are used on ``String`` markers. ``~=``
+and ``====`` (legacy arbitrary equivalence) are not supported on string fields.
 
 User supplied constants are always encoded as strings with either ``'`` or
 ``"`` quote marks. Note that backslash escapes are not defined, but existing