[PATCH v2] docs/misra: add R13.2 and R18.2 to rules.rst

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

Add MISRA C rules 13.2 and 18.2 to rules.rst. Both rules have zero
violations reported by Eclair but they have some cautions. We accept
both rules and for now we'll enable scanning for them in Eclair but only
violations will cause the Gitlab CI job to fail (cautions will not.)

Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxx>
---
Changes in v2:
- clarify that new code is expected to follow the rule
---
 docs/misra/rules.rst | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/docs/misra/rules.rst b/docs/misra/rules.rst
index 7b366edb07..3c2c5e5ac1 100644
--- a/docs/misra/rules.rst
+++ b/docs/misra/rules.rst
@@ -462,6 +462,16 @@ maintainers if you want to suggest a change.
      - Initializer lists shall not contain persistent side effects
      -
 
+   * - `Rule 13.2 
<https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_13_02.c>`_
+     - Required
+     - The value of an expression and its persistent side-effects shall
+       be the same under all permitted evaluation orders
+     - Be aware that the static analysis tool Eclair might report
+       several findings for Rule 13.2 of type "caution". These are
+       instances where Eclair is unable to verify that the code is valid
+       in regard to Rule 13.2. Caution reports are not violations.
+       Regardless, new code is expected to follow this rule.
+
    * - `Rule 13.6 
<https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_13_06.c>`_
      - Required
      - The operand of the sizeof operator shall not contain any
@@ -583,6 +593,16 @@ maintainers if you want to suggest a change.
        submitting new patches please try to decrease the number of
        violations when possible.
 
+   * - `Rule 18.2 
<https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_18_02.c>`_
+     - Required
+     - Subtraction between pointers shall only be applied to pointers
+       that address elements of the same array
+     - Be aware that the static analysis tool Eclair might report
+       several findings for Rule 18.2 of type "caution". These are
+       instances where Eclair is unable to verify that the code is valid
+       in regard to Rule 18.2. Caution reports are not violations.
+       Regardless, new code is expected to follow this rule.
+
    * - `Rule 18.3 
<https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_18_03.c>`_
      - Required
      - The relational operators > >= < and <= shall not be applied to objects 
of pointer type except where they point into the same object
-- 
2.25.1