doc: nrfconnect: clarify mcumgr usage

[greg-fer]

Added a note about issues with mcumgr and BLE adapter.
Rephrased deprecated step.
Moved note to avoid breaking step order.

Signed-off-by: Grzegorz Ferenc Grzegorz.Ferenc@nordicsemi.no

Problem

An mcumgr-related issue can hinder connection to the nRF device.

Change overview

Added a note with a build command that enables using BT HCI device.
Plus made some secondary style changes on the same page.

Testing

Doc changes only.

[github-actions]

Size increase report for "esp32-example-build" from 371fb31

File	Section	File	VM
chip-bridge-app.elf	.flash.text	-48	-48
chip-ipv6only-app.elf	.flash.text	-172	-172
chip-lock-app.elf	.flash.text	-68	-68
chip-shell.elf	.flash.text	-56	-56

Full report output

BLOAT REPORT

Files found only in the build output:
    report.csv

Comparing ./master_artifact/chip-pigweed-app.elf and ./pull_artifact/chip-pigweed-app.elf:

sections,vmsize,filesize

Comparing ./master_artifact/chip-bridge-app.elf and ./pull_artifact/chip-bridge-app.elf:

sections,vmsize,filesize
[Unmapped],0,48
.flash.text,-48,-48

Comparing ./master_artifact/chip-ipv6only-app.elf and ./pull_artifact/chip-ipv6only-app.elf:

sections,vmsize,filesize
.flash.text,-172,-172
[Unmapped],0,-3924

Comparing ./master_artifact/chip-temperature-measurement-app.elf and ./pull_artifact/chip-temperature-measurement-app.elf:

sections,vmsize,filesize

Comparing ./master_artifact/chip-lock-app.elf and ./pull_artifact/chip-lock-app.elf:

sections,vmsize,filesize
[Unmapped],0,68
.flash.text,-68,-68

Comparing ./master_artifact/chip-all-clusters-app.elf and ./pull_artifact/chip-all-clusters-app.elf:

sections,vmsize,filesize

Comparing ./master_artifact/chip-persistent-storage.elf and ./pull_artifact/chip-persistent-storage.elf:

sections,vmsize,filesize

Comparing ./master_artifact/chip-shell.elf and ./pull_artifact/chip-shell.elf:

sections,vmsize,filesize
[Unmapped],0,56
.flash.text,-56,-56

[github-actions]

Size increase report for "gn_qpg-example-build" from 4ec39e2

File	Section	File	VM
chip-qpg6100-lighting-example.out	.heap	0	232
chip-qpg6100-lighting-example.out	.bss	0	-232
chip-qpg6100-lighting-example.out	.text	-8368	-8368

Full report output

BLOAT REPORT

Files found only in the build output:
    report.csv

Comparing ./master_artifact/chip-qpg6100-lighting-example.out.map and ./pull_artifact/chip-qpg6100-lighting-example.out.map:

BLOAT EXECUTION FAILED WITH CODE 1:
bloaty: unknown file type for file './pull_artifact/chip-qpg6100-lighting-example.out.map'

Comparing ./master_artifact/chip-qpg6100-lighting-example.out and ./pull_artifact/chip-qpg6100-lighting-example.out:

sections,vmsize,filesize
[Unmapped],0,8368
.heap,232,0
.shstrtab,0,3
.debug_ranges,0,-24
.debug_aranges,0,-40
.debug_frame,0,-72
.strtab,0,-79
.debug_str,0,-165
.debug_abbrev,0,-207
.bss,-232,0
.symtab,0,-240
.debug_loc,0,-519
.debug_info,0,-588
.debug_line,0,-649
.text,-8368,-8368