Various improvements to FiniteField_pari_ffelt

[jdemeyer]

Apply: attachment: 15125_fix_ffelt.patch, attachment: 15125-reviewer.patch, attachment: 15125_ffelt_to_gp.patch

Depends on #15124

CC: @pjbruin

Component: finite rings

Author: Jeroen Demeyer

Reviewer: Peter Bruin

Merged: sage-5.12.beta5

Issue created by migration from https://trac.sagemath.org/ticket/15125

[jdemeyer]

Attachment: 15125_fix_ffelt.patch.gz

[jdemeyer]

Author: Jeroen Demeyer

[pjbruin]

Description changed:

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+++ 
@@ -1 +1,2 @@
+Apply: [attachment: 15125_fix_ffelt.patch](https://github.com/sagemath/sage-prod/files/10658365/15125_fix_ffelt.patch.gz)
 

[pjbruin]

Reviewer: Peter Bruin

[pjbruin]

reviewer patch

[pjbruin]

comment:4

Attachment: 15125-reviewer.patch.gz

The reviewer patch makes the following small changes:

• no longer include interrupt.pxi (pari_err.pxi suffices)
• fix inaccurate docstrings
• delete an unnecessary conversion (Cython is more efficient when the conversion is left implicit)

[pjbruin]

Description changed:

--- 
+++ 
@@ -1,2 +1,2 @@
-Apply: [attachment: 15125_fix_ffelt.patch](https://github.com/sagemath/sage-prod/files/10658365/15125_fix_ffelt.patch.gz)
+Apply: [attachment: 15125_fix_ffelt.patch](https://github.com/sagemath/sage-prod/files/10658365/15125_fix_ffelt.patch.gz), [attachment: 15125-reviewer.patch](https://github.com/sagemath/sage-prod/files/10658366/15125-reviewer.patch.gz)
 

[jdemeyer]

Description changed:

--- 
+++ 
@@ -1,2 +1 @@
-Apply: [attachment: 15125_fix_ffelt.patch](https://github.com/sagemath/sage-prod/files/10658365/15125_fix_ffelt.patch.gz), [attachment: 15125-reviewer.patch](https://github.com/sagemath/sage-prod/files/10658366/15125-reviewer.patch.gz)
-
+Apply: [attachment: 15125_fix_ffelt.patch](https://github.com/sagemath/sage-prod/files/10658365/15125_fix_ffelt.patch.gz), [attachment: 15125-reviewer.patch](https://github.com/sagemath/sage-prod/files/10658366/15125-reviewer.patch.gz), [attachment: 15125_ffelt_to_gp.patch](https://github.com/sagemath/sage-prod/files/10658367/15125_ffelt_to_gp.patch.gz)