link to GDB GEF on doc

[therealdreg]

Description/Motivation/Screenshots

From GEF docs the user can click to GEF-EXTRAS and is redirected (no target blank) to GEF-EXTRAS, just adding the opposite in the same way for better user experience when navigate

How Has This Been Tested ?

"Tested" indicates that the PR works and the unit test (i.e. make test) run passes without issue.

• [X] x86-32
• [X] x86-64
• [X] ARM
• [X] AARCH64
• [X] MIPS
• [X] POWERPC
• [X] SPARC
• [X] RISC-V

Checklist

• [X] My code follows the code style of this project.
• [X] My change includes a change to the documentation, if required.
• [X] If my change adds new code, adequate tests have been added.
• [X] I have read and agree to the CONTRIBUTING document.

[hugsy]

Why adding the link to the same doc? I believe you meant to add the link to GEF no?

[therealdreg]

Why adding the link to the same doc? I believe you meant to add the link to GEF no?

omg, sorry my fault, fixed!