docs: Fix many spelling mistakes.

Signed-off-by: Anders Kaseorg <anders@zulip.com>

docs/overview/changelog.md

@@ -305,7 +305,7 @@ log][commit-log] for an up-to-date list of raw changes.
 - Improved formatting for Grafana integration.
 - Fixed previews of Dropbox image links.
 - Fixed support for storing avatars/emoji in non-S3 upload backends.
-- Fixed an overly strict database constaint for code playgrounds.
+- Fixed an overly strict database constraint for code playgrounds.
 - Tagged user status strings for translation.
 - Updated translation data from Transifex.
 
@@ -405,7 +405,7 @@ log][commit-log] for an up-to-date list of raw changes.
 - Added new [release lifecycle documentation](../overview/release-lifecycle.md).
 - Added support for subscribing another stream's membership to a stream.
 - Added RealmAuditLog for most settings state changes in Zulip; this
-  data will fascilitate future features showing a log of activity by
+  data will facilitate future features showing a log of activity by
   a given user or changes to an organization's settings.
 - Added support for using Sentry for processing backend exceptions.
 - Added documentation for using `wal-g` for continuous PostgreSQL backups.
@@ -492,7 +492,7 @@ log][commit-log] for an up-to-date list of raw changes.
   `can_create_user` and `can_forge_sender` (used for mirroring).
 - Various API endpoints creating objects now return the ID of the
   created object.
-- Fixed screenreader accessibility of many components, including
+- Fixed screen reader accessibility of many components, including
   the compose box, message editing, popovers, and many more.
 - Fixed transparency issues uploading some animated GIFs as custom emoji.
 - Improved positioning logic for inline YouTube previews.
@@ -822,7 +822,7 @@ log][commit-log] for an up-to-date list of raw changes.
   mobile apps.
 - Removed the legacy websockets-based system for sending messages. This
   system was always a hack, was only ever used for one endpoint, and
-  did not provide a measureable latency benefit over HTTP/2.
+  did not provide a measurable latency benefit over HTTP/2.
 
 ## Zulip 2.1.x series
 
@@ -1131,7 +1131,7 @@ details.
 - Fixed buggy rendering of bulleted lists inside blockquotes.
 - Fixed several bugs with CORS in the nginx configuration.
 - Fixed error message for GitHub login attempts with a deactivated account.
-- Fixed email gateway issues with non-latin characters in stream names.
+- Fixed email gateway issues with non-Latin characters in stream names.
 - Fixed endless re-synchronization of LDAP user avatars (which
   could cause user-visible performance issues for desktop/web clients).
 - Fixed all known bugs with advanced LDAP data synchronization.
@@ -1844,7 +1844,7 @@ running a version from before 1.7 should upgrade directly to 1.7.1.
 #### Full feature changelog
 
 - Simplified the process for installing a new Zulip server, as well as
-  fixing the most common roadbumps and confusing error messages.
+  fixing the most common road bumps and confusing error messages.
 - Added a new "incoming webhook" bot type, limited to only sending
   messages into Zulip, for better security.
 - Added experimental support for outgoing webhooks.
@@ -1928,7 +1928,7 @@ running a version from before 1.7 should upgrade directly to 1.7.1.
 - Fixed zombie process leaks on servers with <4GB of RAM.
 - Fixed Markdown previews of /me messages.
 - Fixed a subtle bug involving timestamps of locally echoed messages.
-- Fixed the behavior of key combintions like Ctrl+Enter in the compose box.
+- Fixed the behavior of key combinations like Ctrl+Enter in the compose box.
 - Worked around Google Compute Engine's default boto configuration,
   which broke Zulip (and any other app using boto).
 - Zulip now will gracefully handle the PostgreSQL server being restarted.
@@ -2403,7 +2403,7 @@ running a version from before 1.7 should upgrade directly to 1.7.1.
   /etc/zulip/secrets.conf.
 - Improved the styling for the Administration page and added tabs.
 - Substantially improved loading performance on slow networks by enabling
-  GZIP compression on more assets.
+  gzip compression on more assets.
 - Changed the page title in narrowed views to include the current narrow.
 - Fixed several backend performance issues affecting very large realms.
 - Fixed bugs where draft compose content might be lost when reloading site.