doc: Add 2.9.1 release to main

Add 2.9.1 release to main

Signed-off-by: divya pillai <[email protected]>

Author: divipillai

doc/nrf/links.txt

@@ -439,6 +439,7 @@
 .. _`nRF Connect SDK latest documentation`: https://docs.nordicsemi.com/bundle/ncs-latest/page/nrf/index.html
 
 .. _`known issues page on the main branch`: https://docs.nordicsemi.com/bundle/ncs-latest/page/nrf/releases_and_maturity/known_issues.html
+.. _`known issues for nRF Connect SDK v2.9.1`: https://docs.nordicsemi.com/bundle/ncs-latest/page/nrf/releases_and_maturity/known_issues.html?v=v2-9-1
 .. _`known issues for nRF Connect SDK v2.9.0-nRF54H20-1-rc3`: https://docs.nordicsemi.com/bundle/ncs-latest/page/nrf/releases_and_maturity/known_issues.html?v=v2-9-0-nRF54H20-1-rc3
 .. _`known issues for nRF Connect SDK v2.9.0`: https://docs.nordicsemi.com/bundle/ncs-latest/page/nrf/releases_and_maturity/known_issues.html?v=v2-9-0
 .. _`known issues for nRF Connect SDK v2.8.0`: https://docs.nordicsemi.com/bundle/ncs-latest/page/nrf/releases_and_maturity/known_issues.html?v=v2-8-0
@@ -495,6 +496,7 @@
 
 .. _`nRF socket options`: https://docs.nordicsemi.com/bundle/ncs-latest/page/nrfxlib/nrf_modem/doc/sockets.html
 
+.. _`Repositories and revisions for v2.9.1`: https://docs.nordicsemi.com/bundle/ncs-2.9.1/page/nrf/releases_and_maturity/repository_revisions.html
 .. _`Repositories and revisions for v2.9.0-nRF54H20-1-rc3`: https://docs.nordicsemi.com/bundle/ncs-2.9.0-nRF54H20-1-rc3/page/nrf/releases_and_maturity/repository_revisions.html
 .. _`Repositories and revisions for v2.9.0`: https://docs.nordicsemi.com/bundle/ncs-2.9.0/page/nrf/releases_and_maturity/repository_revisions.html
 .. _`Repositories and revisions for v2.8.0`: https://docs.nordicsemi.com/bundle/ncs-2.8.0/page/nrf/releases_and_maturity/repository_revisions.html
@@ -529,6 +531,7 @@
 .. _`Repositories and revisions for v1.9.1`: https://docs.nordicsemi.com/bundle/ncs-1.9.1/page/nrf/introduction.html#repositories_and_revisions
 .. _`Repositories and revisions`: https://docs.nordicsemi.com/bundle/ncs-1.9.0/page/nrf/introduction.html#repositories_and_revisions
 
+.. _`Modem library changelog for v2.9.1`: https://docs.nordicsemi.com/bundle/ncs-2.9.1/page/nrfxlib/nrf_modem/doc/CHANGELOG.html#nrf-modem-changelog
 .. _`Modem library changelog for v2.9.0`: https://docs.nordicsemi.com/bundle/ncs-2.9.0/page/nrfxlib/nrf_modem/doc/CHANGELOG.html#nrf-modem-changelog
 .. _`Modem library changelog for v2.8.0`: https://docs.nordicsemi.com/bundle/ncs-2.8.0/page/nrfxlib/nrf_modem/doc/CHANGELOG.html#nrf-modem-changelog
 .. _`Modem library changelog for v2.7.0`: https://docs.nordicsemi.com/bundle/ncs-2.7.0/page/nrfxlib/nrf_modem/doc/CHANGELOG.html#nrf-modem-changelog
@@ -559,6 +562,7 @@
 .. _`Modem library changelog for v1.9.1`: https://docs.nordicsemi.com/bundle/ncs-1.9.1/page/nrfxlib/nrf_modem/doc/CHANGELOG.html
 .. _`Modem library changelog for v1.9.0`: https://docs.nordicsemi.com/bundle/ncs-1.9.0/page/nrfxlib/nrf_modem/doc/CHANGELOG.html
 
+.. _`LwM2M carrier library changelog for v2.9.1`: https://docs.nordicsemi.com/bundle/ncs-2.9.1/page/nrf/libraries/bin/lwm2m_carrier/CHANGELOG.html#liblwm2m-carrier-changelog
 .. _`LwM2M carrier library changelog for v2.9.0`: https://docs.nordicsemi.com/bundle/ncs-2.9.0/page/nrf/libraries/bin/lwm2m_carrier/CHANGELOG.html#liblwm2m-carrier-changelog
 .. _`LwM2M carrier library changelog for v2.8.0`: https://docs.nordicsemi.com/bundle/ncs-2.8.0/page/nrf/libraries/bin/lwm2m_carrier/CHANGELOG.html#liblwm2m-carrier-changelog
 .. _`LwM2M carrier library changelog for v2.7.0`: https://docs.nordicsemi.com/bundle/ncs-2.7.0/page/nrf/libraries/bin/lwm2m_carrier/CHANGELOG.html#liblwm2m-carrier-changelog