[flang][docs] Update meeting link for technical call and some cleanup (llvm#81147)

Added the meeting numbers and passcodes for both the technical and
community calls, just in case. Removed an obsolete reference to "LLVM
flang and current flang". Some minor stylistic edits.

Author: tarunprabhu

flang/docs/GettingInvolved.md

@@ -44,17 +44,21 @@ To understand the status of various developments in Flang please join the respec
 
 ### Flang Community Biweekly Call
 
--   General updates on the Flang Project, both LLVM Flang and current Flang.
+-   General updates on the Flang project.
 -   Join [Flang Community Biweekly Call](https://lanl-us.webex.com/lanl-us/j.php?MTID=mdce13c9bd55202e8071d8128fb953614)
--   Time: On Wednesdays 8:30 Pacific Time, on the weeks alternating with regular Flang Community Technical Biweekly Call.
+    - Meeting number: 177 400 7047
+    - Password: 6PCdCYKmN43
+-   Time: Wednesdays, 8:30 a.m. Pacific Time, on the weeks alternating with regular Flang Community Technical Biweekly Call.
 -   Meeting minutes are available in this [Google Doc](https://docs.google.com/document/d/1Z2U5UAtJ-Dag5wlMaLaW1KRmNgENNAYynJqLW2j2AZQ/edit).
 -   Minutes from older meetings were posted on the [Flang forum](https://discourse.llvm.org/c/subprojects/flang). Search for `Flang Biweekly Sync - Notes`.
 
 ### Flang Community Technical Biweekly Call
 
 -   Technical topics call.
--   Join [Flang Community Technical Biweekly Call](https://bluejeans.com/284530575)
--   Time: On Mondays 8:30 Pacific Time, on the weeks alternating with regular Flang Community Biweekly Call.
+-   Join [Flang Community Technical Biweekly Call](https://teams.microsoft.com/l/meetup-join/19%3ameeting_YWU1NzU4ZjQtOTljOS00NWU1LTg5NjktYTUzOTU3MGEwMzAx%40thread.v2/0?context=%7b%22Tid%22%3a%22f34e5979-57d9-4aaa-ad4d-b122a662184d%22%2c%22Oid%22%3a%223641875c-ef5b-4767-8105-0787a195852f%22%7d)
+    - Meeting ID: 330 223 778 657
+    - Passcode: 7GjaJ3
+-   Time: Mondays, 8:30 a.m. Pacific Time, on the weeks alternating with regular Flang Community Biweekly Call.
 -   The agenda is in this [Google Doc](https://docs.google.com/document/d/1Z2U5UAtJ-Dag5wlMaLaW1KRmNgENNAYynJqLW2j2AZQ/).
 
 ### LLVM Alias Analysis Technical Call