doc: apply sentence case to headers in doc/guides

PR-URL: https://github.com/nodejs/node/pull/37506
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Pooja D P <Pooja.D.P@ibm.com>
Reviewed-By: Harshitha K P <harshitha014@gmail.com>
Reviewed-By: Darshan Sen <raisinten@gmail.com>

doc/guides/commit-queue.md

@@ -1,4 +1,4 @@
-# Commit Queue
+# Commit queue
 
 > Stability: 1 - Experimental
 
@@ -37,7 +37,7 @@ From a high-level, the Commit Queue works as follow:
       3. Close the PR
       4. Go to next PR in the queue
 
-## Current Limitations
+## Current limitations
 
 The Commit Queue feature is still in early stages, and as such it might not
 work for more complex Pull Requests. These are the currently known limitations
@@ -106,7 +106,7 @@ If no errors happen during `git node land`, the script will use the
 `Landed in ...` comment in the PR, and then will close it. Iteration continues
 until all PRs have done the steps above.
 
-## Reverting Broken Commits
+## Reverting broken commits
 
 Reverting broken commits is done manually by Collaborators, just like when
 commits are landed manually via `git node land`. An easy way to revert is a

doc/guides/diagnostic-tooling-support-tiers.md

@@ -1,4 +1,4 @@
-# Diagnostic Tooling Support Tiers
+# Diagnostic tooling support tiers
 
 Diagnostic tooling is important to the consumers of Node.js. It is used both
 in development and in production in order to investigate problems.  The failure

doc/guides/investigating_native_memory_leak.md

@@ -1,4 +1,4 @@
-# Investigating Memory Leaks with valgrind
+# Investigating memory leaks with valgrind
 
 A Node.js process may run out of memory due to excessive consumption of
 native memory. Native Memory is memory which is not managed by the

doc/guides/maintaining-icu.md

@@ -33,7 +33,7 @@ $ node -p process.versions
 }
 ```
 
-### Time Zone Data
+### Time zone data
 
 Time zone data files are updated independently of ICU CLDR data.  ICU and its
 main data files do not need to be upgraded in order to apply time zone data file
@@ -50,7 +50,7 @@ in the icu/icu-data repository.
 All modern versions of Node.js use the version 44 ABI of the time zone data
 files.
 
-#### Example: Updating the ICU `.dat` File
+#### Example: updating the ICU `.dat` file
 
 * Decompress `deps/icu/source/data/in/icudt##l.dat.bz2`, where `##` is
   the ICU major version number.
@@ -68,7 +68,7 @@ files.
 * Build, test, verifying `process.versions.tz` matches the desired version.
 * Create a new minor version release.
 
-## Release Schedule
+## Release schedule
 
 ICU typically has >1 release a year, particularly coinciding with a major
 release of [Unicode][]. The current release schedule is available on the [ICU][]
@@ -237,7 +237,7 @@ You should see a message such as:
 INFO: Using floating patch "tools/icu/patches/63/source/tools/toolutil/pkg_genc.cpp" from "tools/icu"
 ```
 
-### Clean Up
+### Clean up
 
 Any patches older than the minimum version given in `tools/icu/icu_versions.json`
 ought to be deleted, because they will never be used.

doc/guides/maintaining-npm.md

@@ -38,7 +38,7 @@ $ git commit -m "doc: update npm LICENSE using license-builder.sh"
 
 Note: please ensure you are only making the updates that are changed by npm.
 
-## Step 4: Apply Whitespace fix
+## Step 4: Apply whitespace fix
 
 ```console
 $ git rebase --whitespace=fix master

doc/guides/maintaining-openssl.md

@@ -22,7 +22,7 @@ currently need to generate three PRs as follows:
 * `nasm` (<https://www.nasm.us/>) Version 2.11 or higher is needed.
 * GNU `as` in binutils. Version 2.26 or higher is needed.
 
-## 0. Check Requirements
+## 0. Check requirements
 
 ```console
 % perl -v

doc/guides/maintaining-root-certs.md

@@ -1,4 +1,4 @@
-# Maintaining the Root Certificates
+# Maintaining the root certificates
 
 Node.js contains a compiled-in set of root certificates used as trust anchors
 for TLS certificate validation.

doc/guides/maintaining-the-build-files.md

@@ -1,4 +1,4 @@
-# Maintaining the Build files
+# Maintaining the build files
 
 This document explains how to maintain the build files in the codebase.