docs: v0.2 docs in master (#21438)

current python.langchain.com is building from branch `v0.1`. Iterate on
v0.2 docs here.

---------

Signed-off-by: Weichen Xu <weichen.xu@databricks.com>
Signed-off-by: Rahul Tripathi <rauhl.psit.ec@gmail.com>
Co-authored-by: Harrison Chase <hw.chase.17@gmail.com>
Co-authored-by: jacoblee93 <jacoblee93@gmail.com>
Co-authored-by: Leonid Ganeline <leo.gan.57@gmail.com>
Co-authored-by: Leonid Kuligin <lkuligin@yandex.ru>
Co-authored-by: Averi Kitsch <akitsch@google.com>
Co-authored-by: Nuno Campos <nuno@langchain.dev>
Co-authored-by: Nuno Campos <nuno@boringbits.io>
Co-authored-by: Bagatur <22008038+baskaryan@users.noreply.github.com>
Co-authored-by: Eugene Yurtsev <eyurtsev@gmail.com>
Co-authored-by: Martín Gotelli Ferenaz <martingotelliferenaz@gmail.com>
Co-authored-by: Fayfox <admin@fayfox.com>
Co-authored-by: Eugene Yurtsev <eugene@langchain.dev>
Co-authored-by: Dawson Bauer <105886620+djbauer2@users.noreply.github.com>
Co-authored-by: Ravindu Somawansa <ravindu.somawansa@gmail.com>
Co-authored-by: Dhruv Chawla <43818888+Dominastorm@users.noreply.github.com>
Co-authored-by: ccurme <chester.curme@gmail.com>
Co-authored-by: Bagatur <baskaryan@gmail.com>
Co-authored-by: WeichenXu <weichen.xu@databricks.com>
Co-authored-by: Benito Geordie <89472452+benitoThree@users.noreply.github.com>
Co-authored-by: kartikTAI <129414343+kartikTAI@users.noreply.github.com>
Co-authored-by: Kartik Sarangmath <kartik@thirdai.com>
Co-authored-by: Sevin F. Varoglu <sfvaroglu@octoml.ai>
Co-authored-by: MacanPN <martin.triska@gmail.com>
Co-authored-by: Prashanth Rao <35005448+prrao87@users.noreply.github.com>
Co-authored-by: Hyeongchan Kim <kozistr@gmail.com>
Co-authored-by: sdan <git@sdan.io>
Co-authored-by: Guangdong Liu <liugddx@gmail.com>
Co-authored-by: Rahul Triptahi <rahul.psit.ec@gmail.com>
Co-authored-by: Rahul Tripathi <rauhl.psit.ec@gmail.com>
Co-authored-by: pjb157 <84070455+pjb157@users.noreply.github.com>
Co-authored-by: Eun Hye Kim <ehkim1440@gmail.com>
Co-authored-by: kaijietti <43436010+kaijietti@users.noreply.github.com>
Co-authored-by: Pengcheng Liu <pcliu.fd@gmail.com>
Co-authored-by: Tomer Cagan <tomer@tomercagan.com>
Co-authored-by: Christophe Bornet <cbornet@hotmail.com>

docs/src/css/custom.css

@@ -36,7 +36,7 @@
   --ifm-code-font-size: 95%;
   --ifm-font-family-base: 'Public Sans';
   --ifm-menu-link-padding-horizontal: 0.5rem;
-  --ifm-menu-link-padding-vertical: 0.375rem;
+  --ifm-menu-link-padding-vertical: 0.5rem;
   --doc-sidebar-width: 275px !important;
 }
 
@@ -197,6 +197,10 @@ nav, h1, h2, h3, h4 {
   opacity: 0.5;
 }
 
+.markdown {
+  line-height: 2em;
+}
+
 .markdown > h2 {
   margin-top: 2rem;
   border-bottom-color: var(--ifm-color-primary);
@@ -243,3 +247,17 @@ nav, h1, h2, h3, h4 {
   background: url("data:image/svg+xml,%3Csvg viewBox='0 0 24 24' xmlns='http://www.w3.org/2000/svg'%3E%3Cpath fill='white' d='M12 .297c-6.63 0-12 5.373-12 12 0 5.303 3.438 9.8 8.205 11.385.6.113.82-.258.82-.577 0-.285-.01-1.04-.015-2.04-3.338.724-4.042-1.61-4.042-1.61C4.422 18.07 3.633 17.7 3.633 17.7c-1.087-.744.084-.729.084-.729 1.205.084 1.838 1.236 1.838 1.236 1.07 1.835 2.809 1.305 3.495.998.108-.776.417-1.305.76-1.605-2.665-.3-5.466-1.332-5.466-5.93 0-1.31.465-2.38 1.235-3.22-.135-.303-.54-1.523.105-3.176 0 0 1.005-.322 3.3 1.23.96-.267 1.98-.399 3-.405 1.02.006 2.04.138 3 .405 2.28-1.552 3.285-1.23 3.285-1.23.645 1.653.24 2.873.12 3.176.765.84 1.23 1.91 1.23 3.22 0 4.61-2.805 5.625-5.475 5.92.42.36.81 1.096.81 2.22 0 1.606-.015 2.896-.015 3.286 0 .315.21.69.825.57C20.565 22.092 24 17.592 24 12.297c0-6.627-5.373-12-12-12'/%3E%3C/svg%3E")
     no-repeat;
 }
+
+.announcementBar_node_modules-\@docusaurus-theme-classic-lib-theme-AnnouncementBar-styles-module {
+  height:40px !important;
+  font-size: 20px !important;
+}
+
+[data-theme='dark'] .announcementBar_node_modules-\@docusaurus-theme-classic-lib-theme-AnnouncementBar-styles-module {
+  background-color: #1b1b1b;
+  color: #fff;
+}
+
+[data-theme='dark'] .announcementBar_node_modules-\@docusaurus-theme-classic-lib-theme-AnnouncementBar-styles-module button {
+  color: #fff;
+}