Switch from flatKeywordList() to flat arrays (#676)

Part of preparations for PR #673

Copied from [my original
comment](#673 (comment)):

I see there is no distinction in the keyword tokens between `all` and
`dataType` / `datatype` / `dataTypes`:


https://github.com/sql-formatter-org/sql-formatter/blob/290f3b767492d5e3204866447f9f4e4c098f825f/src/languages/postgresql/postgresql.keywords.ts#L4-L8


https://github.com/sql-formatter-org/sql-formatter/blob/290f3b767492d5e3204866447f9f4e4c098f825f/src/languages/transactsql/transactsql.functions.ts#L78-L83


https://github.com/sql-formatter-org/sql-formatter/blob/290f3b767492d5e3204866447f9f4e4c098f825f/src/languages/snowflake/snowflake.keywords.ts#L102-L106


https://github.com/sql-formatter-org/sql-formatter/blob/290f3b767492d5e3204866447f9f4e4c098f825f/src/languages/transactsql/transactsql.functions.ts#L303-L309

This is because of the `flatKeywordList()` function, which effectively
discards the key information:


https://github.com/sql-formatter-org/sql-formatter/blob/290f3b767492d5e3204866447f9f4e4c098f825f/src/utils.ts#L18-L20

Because of this, I would like to simplify the
`src/languages/*/*.keywords.ts` files to export 1 flat array (with empty
lines + comments as separators instead of object keys) and delete the
`flatKeywordList()` function - this will prevent unusual, inconsistent
naming conventions and also clarify that the object keys do nothing.

## Reviewer notes

1. Best to review this with whitespace changes turned off:
https://github.com/sql-formatter-org/sql-formatter/pull/676/files?w=1
2. This PR also enables GitHub Actions workflows CI for pull requests on
branches other than `master` and `develop`, so that PRs from community
members can be tested on GitHub Actions
3. while removing the object keys, I added comments as such:
a. if there was a commented URL above the key, I removed the key and
left the URL as the sole comment (eg. in
`src/languages/db2i/db2i.functions.ts`)
b. if there was no other comment (or if the commented URL was generic,
for multiple sections), I left the key name as the comment (eg. in
`src/languages/hive/hive.functions.ts`)

.github/workflows/coveralls.yaml

@@ -13,10 +13,10 @@ jobs:
         node-version: [18.x]
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
 
       - name: Use Node.js ${{ matrix.node-version }}
-        uses: actions/setup-node@v1
+        uses: actions/setup-node@v4
         with:
           node-version: ${{ matrix.node-version }}
 

.github/workflows/webpack.yaml

@@ -2,7 +2,6 @@ name: webpack
 
 on:
   pull_request:
-    branches: [master, develop]
 
 jobs:
   build:
@@ -13,10 +12,10 @@ jobs:
         node-version: [18.x]
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
 
       - name: Use Node.js ${{ matrix.node-version }}
-        uses: actions/setup-node@v1
+        uses: actions/setup-node@v4
         with:
           node-version: ${{ matrix.node-version }}