fix redirection links in docs

[ariel-anieli]

Hello,

• here are commits for fixing redirection links
• it started from noticing that, in gen_statem, the Note didn't point to the Design Principles
• noticed the same pattern in other files.

# git grep -Pn '\[OTP Design Principles\]'

lib/kernel/doc/kernel_app.md:50:manager (see [OTP Design Principles](`e:system:design_principles.md`) and
lib/kernel/doc/references/app.md:173:  information, see [OTP Design Principles](`e:system:applications.md`).
lib/kernel/doc/references/config.md:150:[OTP Design Principles](`e:system:design_principles.md`)
lib/kernel/src/application.erl:43:[OTP Design Principles](`e:system:design_principles.md`).
lib/kernel/src/application.erl:47:[OTP Design Principles](`e:system:design_principles.md`),
lib/kernel/src/error_logger.erl:38:[OTP Design Principles](`e:system:design_principles.md`) and `m:gen_event`),
lib/sasl/doc/guides/sasl_intro.md:36:section [OTP Design Principles](`e:system:index.html`) in _System
lib/sasl/doc/references/appup.md:82:[OTP Design Principles](`e:system:release_handling.md`) in _System
lib/sasl/src/release_handler.erl:29:[OTP Design Principles](`e:system:release_handling.md`) in _System
lib/sasl/src/release_handler.erl:215:[OTP Design Principles](`e:system:index.html`),
lib/stdlib/src/gen_event.erl:31:For more information, see [OTP Design Principles](`e:system:events.md`).
lib/stdlib/src/gen_event.erl:366:For more information, see [OTP Design Principles](`e:system:index.html`).
lib/stdlib/src/gen_fsm.erl:209:see [OTP Design Principles](`e:system:design_principles`).
lib/stdlib/src/gen_fsm.erl:683:[OTP Design Principles](`e:system:release_handling.md#instr`).
lib/stdlib/src/gen_statem.erl:33:see [OTP Design Principles](`e:system:statem.md`).
lib/stdlib/src/gen_statem.erl:40:> the User's Guide [OTP Design Principles](`e:system:index.html`)
lib/stdlib/src/gen_statem.erl:1742:[OTP Design Principles](`e:system:release_handling.md#instr`).
lib/stdlib/src/proc_lib.erl:26:[OTP Design Principles](`e:system:design_principles.md`). Specifically, the
system/doc/README.md:12:* [OTP Design Principles](design_principles/design_principles.md) -
system/doc/getting_started/conc_prog.md:626:  [OTP Design Principles](`e:system:design_principles.md`)).
system/doc/reference_manual/modules.md:167:[OTP Design Principles](`e:system:spec_proc.md#behaviours`).
system/doc/reference_manual/ref_man_processes.md:504:[OTP Design Principles](`e:system:design_principles.md`)
system/doc/system_principles/system_principles.md:141:[OTP Design Principles](`e:system:release_handling.md`) and the

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CT Test Results

    4 files    162 suites   2h 16m 35s ⏱️
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4 362 runs  4 020 ✅ 341 💤 1 ❌

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// Erlang/OTP Github Action Bot

[garazdawi]

Many of these links are to sections within the "OTP Design Principles" Guide, so the link is correct, it is just the description that is a bit missleading. I've added some proposals to make things clearer, what do you think?

[ariel-anieli]

Many of these links are to sections within the "OTP Design Principles" Guide, so the link is correct, it is just the description that is a bit missleading. I've added some proposals to make things clearer, what do you think?

Thanks for the feedback, @garazdawi. Maybe I should explain how I thought the links work.
Tell me, does it makes sense?

• I noticed gen_statem has a note to the Design Principles
• the displayed text is Design Principles, but here is the link points to the System Documentation, https://www.erlang.org/doc/system/
• in fact, the Design Principles are https://www.erlang.org/doc/system/design_principles
• therefore the changes;

# git diff master lib/stdlib/src/gen_statem.erl
diff --git a/lib/stdlib/src/gen_statem.erl b/lib/stdlib/src/gen_statem.erl
index 150ba7455b..875374fd7b 100644
--- a/lib/stdlib/src/gen_statem.erl
+++ b/lib/stdlib/src/gen_statem.erl
@@ -30,14 +30,14 @@ A generic state machine server process (`gen_statem`) implemented
 using this module has a standard set of interface functions
 and includes functionality for tracing and error reporting.
 It also fits into an OTP supervision tree.  For more information,
-see [OTP Design Principles](`e:system:statem.md`).
+see [OTP Design Principles](`e:system:design_principles.md`).
 
 > #### Note {: .info }
 >
 > If you are new to `gen_statem` and want an overview
 > of concepts and operation the section
 > [`gen_statem` Behaviour](`e:system:statem.md`) located in
-> the User's Guide [OTP Design Principles](`e:system:index.html`)
+> the User's Guide [OTP Design Principles](`e:system:design_principles.md`)
 > is recommended to read.  This reference manual focuses on
 > being correct and complete, which might make it hard to see
 > the forest for all the trees.
@@ -1739,7 +1739,7 @@ its internal state during a release upgrade/downgrade, that is,
 when the instruction `{update, Module, Change, ...}`,
 where `Change = {advanced, Extra}`, is specified in
 the [`appup`](`e:sasl:appup.md`) file.  For more information, see
-[OTP Design Principles](`e:system:release_handling.md#instr`).
+[OTP Design Principles](`e:system:design_principles.md#release-handling`).
 
 For an upgrade, `OldVsn` is `Vsn`, and for a downgrade, `OldVsn` is
 `{down, Vsn}`. `Vsn` is defined by the `vsn` attribute(s)

[garazdawi]

Maybe I should explain how I thought the links work. Tell me, does it makes sense?

• I noticed gen_statem has a note to the Design Principles
• the displayed text is Design Principles, but here is the link points to the System Documentation, https://www.erlang.org/doc/system/

I agree with you in the bullets above

• in fact, the Design Principles are https://www.erlang.org/doc/system/design_principles

but here I think the confusion comes. There is indeed a page with a URI called "design_principles", but if you check the title of that page it is the "Overview" page. There are many pages within the Design Principles Guide and the statem page is one of them. You can see which pages are part of the Guide in the navigation bar to the left.

[ariel-anieli]

Gotcha, @garazdawi: Design Principles is a set of pages. I'm updating the PR along your feedback.

[garazdawi]

I think you may have forgotten to push your updated?

[ariel-anieli]

I think you may have forgotten to push your updated?

Yes, @garazdawi; bear with me, I'm pushing them by tomorrow.

[garazdawi]

No rush, just wanted to ping you incase it was a mistake.

[ariel-anieli]

No rush, just wanted to ping you incase it was a mistake.

There you are, @garazdawi; thanks for the heads up. I've just pushed a version.